#include <iostream>
#include <vector>
#include <algorithm>
#include <set>
using namespace std;
using ll = long long;
using vi = vector<int>;
using vvi = vector<vi>;
using vll = vector<ll>;
using vvll = vector<vll>;
using pll = pair<ll, ll>;
using vpll = vector<pll>;
#define sz(x) int(x.size())
const int mx = 100'000;
const int lg = 17;
const ll INF = 2'000'000'000'000'000'00LL;
int n, q;
ll w;
vi a(1+mx), b(1+mx);
vll c(1+mx);
vi edge[1+mx];
vpll edgepair[1+mx];
multiset<ll> centmaxvals;
multiset<ll> subtreemaxvals[1+mx];
vi banned(1+mx, 0);
//nodes & edges indexed from 1, everything else from 0
vi depth(1+mx);
vi subtree(1+mx);
int cent;
void dfs0(int u, int p, vi& lst)
{
lst.push_back(u);
subtree[u] = 1;
for(int v : edge[u])
{
if(v == p) continue;
if(banned[v]) continue;
depth[v] = 1 + depth[u];
dfs0(v, u, lst);
subtree[u] += subtree[v];
}
}
vi grouplist[1+mx]; //done
vi centsubtree[1+mx]; //done
vi centnormdepth[1+mx]; //done
vll centnormdist[1+mx]; //done
vi centanc[1+mx]; //done
int centancind[1+mx][1+lg]; //done
int currind; //done
vi currnodeind(1+mx); //done
vi centprocessord; //done
vi centtreedepth(1+mx, 0); //done
vi reprlist[1+mx];
void dfs1(int u, int p)
{
//this is preset to -1 for the root and p == u !!!
for(pll vp : edgepair[u])
{
int v = vp.first;
ll w = vp.second;
if(v == p) continue;
if(banned[v]) continue;
// cerr << "used edge : " << u << " -> " << v << " at " << w << '\n';
currind++;
currnodeind[v] = currind;
grouplist[cent][currind] = v;
centsubtree[cent][currind] = 1;
centnormdepth[cent][currind] = 1 + centnormdepth[cent][ currnodeind[u] ];
centnormdist[cent][currind] = w + centnormdist[cent][ currnodeind[u] ];
// cerr << "centnormdist " << cent << ' ' << currind << " = " << centnormdist[cent][currind] << '\n';
dfs1(v, u);
centsubtree[cent][ currnodeind[u] ] += centsubtree[cent][ currnodeind[v] ];
}
}
struct segtree
{
int S;
int Z;
vi l, r;
vll mxv, lp;
segtree()
{
;
}
void build(int i, int L, int R, vll& lst)
{
l[i] = L;
r[i] = R;
if(l[i] == r[i])
{
mxv[i] = lst[l[i]];
}
else
{
build(2*i, L, (L+R)/2, lst);
build(2*i+1, (L+R)/2+1, R, lst);
mxv[i] = max(mxv[2*i], mxv[2*i+1]);
}
}
void add(int i, int L, int R, ll V)
{
if(R < l[i] || r[i] < L) return;
else if(L <= l[i] && r[i] <= R)
{
mxv[i] += V;
lp[i] += V;
}
else
{
add(2*i, L, R, V);
add(2*i+1, L, R, V);
mxv[i] = lp[i] + max(mxv[2*i], mxv[2*i+1]);
}
}
ll rangemax(int i, int L, int R)
{
if(R < l[i] || r[i] < L) return -INF;
else if(L <= l[i] && r[i] <= R) return mxv[i];
else return lp[i] + max(rangemax(2*i, L, R), rangemax(2*i+1, L, R));
}
segtree(vll& lst)
{
S = sz(lst);
Z = 4*S;
l = r = vi(1+Z);
mxv = lp = vll(1+Z, 0);
build(1, 0, sz(lst)-1, lst);
}
};
segtree CST[1+mx]; //done
bool firstbuild = 1;
int build(int u)
{
// cerr << "building " << u << '\n';
depth[u] = 0;
cent = -1;
vi lst;
dfs0(u, u, lst);
// cerr << "X\n";
if(firstbuild) firstbuild = 0;
else
{
for(int f : lst)
{
reprlist[f].push_back(u);
}
}
for(int k : lst)
{
if(2*subtree[k] < sz(lst)) continue;
if(cent == -1 || depth[k] > depth[cent])
cent = k;
}
centprocessord.push_back(cent);
// cerr << "F\n";
grouplist[cent] = centsubtree[cent] = centnormdepth[cent] = vi(sz(lst));
centnormdist[cent] = vll(sz(lst));
currind = 0;
currnodeind[cent] = 0;
// cerr << "Z\n";
grouplist[cent][0] = cent;
centsubtree[cent][0] = 1;
centnormdepth[cent][0] = 0;
centnormdist[cent][0] = 0;
// cerr << "Y\n";
dfs1(cent, cent);
// cerr << "\n\n\n";
// cerr << "currently building centroid = " << cent << '\n';
// cerr << "grouplist = ";
// for(int z : grouplist[cent]) cerr << z << ' ';
// cerr << '\n';
// cerr << "distances = ";
// for(ll z : centnormdist[cent]) cerr << z << ' ';
// cerr << '\n';
CST[cent] = segtree(centnormdist[cent]);
int localcent = cent;
banned[localcent] = 1;
// cerr << "Z\n";
for(int z : edge[localcent])
{
if(banned[z]) continue;
// cerr << "build : " << cent << " -> " << z << '\n';
int d = build(z);
centanc[d].push_back(localcent);
}
banned[localcent] = 0;
return localcent;
};
ll gettwosum(int u)
{
auto it = subtreemaxvals[u].rbegin();
auto it2 = it;
it2++;
return *it + *it2;
}
void disablemax(int u)
{
centmaxvals.erase(gettwosum(u));
}
void enablemax(int u)
{
centmaxvals.insert(gettwosum(u));
}
int main()
{
ios_base::sync_with_stdio(false);
cin.tie(NULL);
cin >> n >> q;
cin >> w;
for(int e = 1; e <= n-1; e++)
{
cin >> a[e] >> b[e] >> c[e];
edge[a[e]].push_back(b[e]);
edge[b[e]].push_back(a[e]);
edgepair[a[e]].push_back({b[e], c[e]});
edgepair[b[e]].push_back({a[e], c[e]});
}
// cerr << "A\n";
//init
for(int i = 1; i <= n; i++)
{
centanc[i].push_back(i);
centancind[i][0] = 0;
}
int rt = build(1);
for(int i = 1; i <= n; i++)
{
// cerr << "\n\n\n seeing reprlist of " << i << "\n";
reprlist[i].push_back(i);
reverse(reprlist[i].begin(), reprlist[i].end());
// for(int t : reprlist[i]) cerr << t << ' ';
// cerr << '\n';
}
// cerr << "B\n";
for(int i = 1; i <= n; i++)
while(centanc[i].back() != rt)
centanc[i].push_back( centanc[ centanc[i].back() ][1] );
// cerr << "B1\n";
for(int u : centprocessord)
{
centtreedepth[u] = sz(centanc[u]) - 1;
}
// cerr << "B2\n";
for(int i = 1; i <= n; i++)
{
for(int z = 0; z < sz(grouplist[i]); z++)
{
int j = grouplist[i][z];
centancind[j][ centtreedepth[j] - centtreedepth[i] ] = z;
}
}
// for(int qv : grouplist[5]) cerr << qv << ' ';
// cerr << '\n';
// cerr << "cent tree depth = ";
// for(int i = 1; i <= n; i++) cerr << centtreedepth[i] << ' ';
// cerr << '\n';
// cerr << "C\n";
// cerr << "5 ind = ";
// for(int i = 1; i <= n; i++) cerr << centancind[i][centtreedepth[i] - centtreedepth[5]] << ' ';
// cerr << '\n';
for(int i = 1; i <= n; i++)
{
// cerr << "\n\n\n";
// cerr << "i = " << i << '\n';
subtreemaxvals[i].insert(0);
subtreemaxvals[i].insert(0);
// for(int h = 0; h < sz(grouplist[i]); h++) cerr << CST[i].rangemax(1, h, h) << ' ';
// cerr << '\n';
for(int j : edge[i])
{
if(centtreedepth[j] <= centtreedepth[i]) continue;
int jrep = reprlist[j][ centtreedepth[j] - centtreedepth[i] ];
// cerr << "checking " << i << " -> " << j << " = " << jrep << '\n';
int dd = centtreedepth[jrep] - centtreedepth[i];
// cerr << "dd = " << dd << '\n';
int jrepid = centancind[jrep][dd];
int jrepst = centsubtree[i][ jrepid ];
// for(int h = 0; h < sz(grouplist[i]); h++)
// cerr << grouplist[i][h] << " - " << centsubtree[i][h] << '\n';
// cerr << "j interval = ";
// cerr << jrepid << ' ' << jrepst << '\n';
// cerr << "#\n";
subtreemaxvals[i].insert(CST[i].rangemax(1, jrepid, jrepid+jrepst-1));
}
// cerr << i << " done\n";
}
// cerr << "D\n";
// cerr << "\n\n\n\n\n";
// for(int i = 1; i <= n; i++)
// {
// cerr << '\n';
// cerr << i << " : ";
// for(int j : grouplist[i]) cerr << j << ' ';
// cerr << '\n';
// cerr << i << " : ";
// for(ll y : subtreemaxvals[i]) cerr << y << ' ';
// cerr << '\n';
// }
// cerr << "\n\n\n\n\n";
// ce
for(int i = 1; i <= n; i++) centmaxvals.insert(gettwosum(i));
// cerr << "preliminary answer = " << *centmaxvals.rbegin() << '\n';
ll last = 0;
for(int j = 1; j <= q; j++)
{
// cerr << "\n\n";
// cerr << "j = " << j << " started\n";
ll d;
ll e;
cin >> d >> e;
// cerr << e << " + " << last << '\n';
d = ((d + last) % ll(n-1)) + 1;
e = (e + last) % w;
// cerr << "actual values = " << d << ' ' << e << '\n';
ll delta = e - c[d];
c[d] = e;
//update
int x = a[d], y = b[d];
if(centtreedepth[x] > centtreedepth[y]) swap(x, y);
int depx = centtreedepth[x], depy = centtreedepth[y];
int depu = depx, depv = depy;
int u = x, v = y;
// cerr << "#\n";
// cerr << "???\n";
// cerr << u << ' ' << depu << " : " << v << ' ' << depv << '\n';
for(int ndep = depx; ndep >= 0; ndep--)
{
// cerr << "\n\n";
// cerr << "ndep = " << ndep <<'\n';
if(centanc[u][depu - ndep] != centanc[v][depv - ndep]) continue;
// cerr << "entered\n";
if(centnormdepth[centanc[u][depu - ndep]][centancind[u][depu - ndep]] > centnormdepth[centanc[v][depv - ndep]][centancind[v][depv - ndep]])
{
swap(u, v);
swap(depu, depv);
}
// cerr << "hello\n";
int a = centanc[u][depu - ndep];
// cerr << "a = " << a << '\n';
// cerr << "segment tree = ";
// for(int li = 0; li < sz(grouplist[a]); li++)
// cerr << CST[a].rangemax(1, li, li) << ' ';
// cerr << "\n";
disablemax(a);
// cerr << "max disabled at " << a << '\n';
// cerr << "index of " << v << " at " << a << " = " << vid << '\n';
int vid = centancind[v][depv - ndep];
// cerr << "index of " << v << " at " << a << " = " << vid << '\n';
int vst = centsubtree[a][vid];
// cerr << "hello\n";
// cerr << a << ' ' << sz(grouplist[a]) << ' ' << vid << ' ' << vst << '\n';
// cerr << "trying to erase " << CST[a].rangemax(1, vid, vid+vst-1) << '\n';
// for(ll rv : subtreemaxvals[a]) cerr << "rv = " << rv << '\n';
// cerr << "inspecting\n";
// cerr << "value erased\n";
int vrep = reprlist[v][depv - ndep];
int vrepid = centancind[vrep][ centtreedepth[vrep] - centtreedepth[a] ];
int vrepst = centsubtree[ a ][ vrepid ];
subtreemaxvals[a].erase(subtreemaxvals[a].find(CST[a].rangemax(1, vrepid, vrepid+vrepst-1)));
// cerr << "reached flag\n";
CST[a].add(1, vid, vid+vst-1, delta);
subtreemaxvals[a].insert(CST[a].rangemax(1, vrepid, vrepid+vrepst-1));
enablemax(a);
}
// cerr << "centroid = 2\n";
// for(ll b : subtreemaxvals[2])
// cerr << "b = " << b << '\n';
// cerr << "\n\n\n\n DECLARING ANSWER\n";
last = *centmaxvals.rbegin();
cout << last << '\n';
}
}
