#include <bits/stdc++.h>
#define lli long long int
#define pb push_back
#define MP make_pair
#define ld long double
#define REP(i, n) for(int i = 0; (i) < (n); (i)++)
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()
using namespace std;
void fastio() {
ios_base::sync_with_stdio(false);
cin.tie(NULL);
}
const int N = 1e5 + 5;
const int INF = 1e9 + 500;
const int LGN = 18;
struct SegT {
vector<lli> st, tag;
int n;
void build(int tl, int tr, int v, vector<int> &x) {
if(tl == tr) {
st[v] = x[tl];
return;
}
int tm = (tl + tr) >> 1;
build(tl, tm, v << 1, x);
build(tm + 1, tr, v << 1 ^ 1, x);
st[v] = max(st[v << 1], st[v << 1 ^ 1]);
}
void reset(int nn) {
n = nn;
st.assign(4*(n + 3), 0);
tag.assign(4*(n + 3), 0);
}
void push(int v) {
st[v << 1] += tag[v];
st[v << 1 ^ 1] += tag[v];
tag[v << 1] += tag[v];
tag[v << 1 ^ 1] += tag[v];
tag[v] = 0;
}
void update(int tl, int tr, int v, int l, int r, int val) {
if(tl >= l && tr <= r) {
st[v] += val;
tag[v] += val;
return;
}
if(tl > r || tr < l) {
return;
}
push(v);
int tm = (tl + tr) >> 1;
update(tl, tm, v << 1, l, r, val);
update(tm + 1, tr, v << 1 ^ 1, l, r, val);
st[v] = max(st[v << 1], st[v << 1 ^ 1]);
}
void update(int l, int r, int val) {
update(0, n, 1, l, r, val);
}
lli query(int tl, int tr, int v, int l, int r) {
if(tl >= l && tr <= r) {
return st[v];
}
if(tl > r || tr < l) {
return 0;
}
push(v);
int tm = (tl + tr) >> 1;
return max(query(tl, tm, v << 1, l, r), query(tm + 1, tr, v << 1 ^ 1, l, r));
}
lli query(int l, int r) {
return query(0, n, 1, l, r);
}
};
int n = 0, q = 0, w = 0;
vector<vector<array<int, 2> > > adj(N, vector<array<int, 2> >());
vector<array<int, 3> > edg;
vector<int> sub(N, 0);
vector<int> vis(N, 0);
array<SegT, LGN> st;
vector<array<int, LGN> > cent(N);
vector<array<int, LGN> > tin(N), p(N), ssz(N);
vector<array<int, LGN> > comp(N);
vector<array<int, LGN> > edgnode(N);
array<int, LGN> tim;
array<vector<int>, LGN> arr;
vector<set<array<int, 2>, greater<array<int, 2> > > > cand(N, set<array<int, 2>, greater<array<int, 2> > >());
vector<vector<array<int, 2> > > cent_adj(N, vector<array<int, 2> >());
set<array<int, 2>, greater<array<int, 2> > > anss;
vector<int> lv(N, 0);
vector<int> cent_res(N, 0);
void dfssz(int node, int par) {
sub[node] = 1;
for(auto c : adj[node]) {
if(c[0] == par || vis[c[0]]) {
continue;
}
dfssz(c[0], node);
sub[node] += sub[c[0]];
}
}
int get_cent(int node, int par, int tar) {
for(auto c : adj[node]) {
if(c[0] == par || vis[c[0]]) continue;
if(sub[c[0]] * 2 > tar) {
return get_cent(c[0], node, tar);
}
}
return node;
}
void prec(int node, int par, int lvl, int centro) {
ssz[node][lvl] = 1;
tin[node][lvl] = tim[lvl]++;
cent[node][lvl] = centro;
for(auto &c : adj[node]) {
if(c[0] == par || vis[c[0]]) continue;
p[c[0]][lvl] = node;
edgnode[c[1]][lvl] = c[0];
prec(c[0], node, lvl, centro);
ssz[node][lvl] += ssz[c[0]][lvl];
}
}
void prec2(int node, int par, int lvl, int g) {
comp[node][lvl] = g;
for(auto c : adj[node]) {
if(c[0] == par || vis[c[0]]) continue;
prec2(c[0], node, lvl, g);
}
}
void prec3(int node, int par, int lvl) {
for(auto c : adj[node]) {
if(c[0] == par || vis[c[0]]) continue;
arr[lvl][tin[c[0]][lvl]] = arr[lvl][tin[node][lvl]] + edg[c[1]][2];
prec3(c[0], node, lvl);
}
}
void centroid_decomp(int node, int lvl) {
dfssz(node, 0);
int centro = get_cent(node, 0, sub[node]);
lv[centro] = lvl;
p[centro][lvl] = 0;
prec(centro, 0, lvl, centro);
for(auto c : adj[centro]) {
if(vis[c[0]]) continue;
cent_adj[centro].pb({c[0], 0});
prec2(c[0], centro, lvl, c[0]);
}
arr[lvl][centro] = 0;
prec3(centro, 0, lvl);
vis[centro] = 1;
for(auto c : adj[node]) {
if(vis[c[0]]) continue;
centroid_decomp(c[0], lvl + 1);
}
}
void solve() {
REP(i, LGN) {
tim[i] = 0;
arr[i].assign(N, 0);
REP(j, N) edgnode[j][i] = -1;
}
cin >> n >> q >> w;
edg.resize(n - 1);
REP(i, n - 1) {
cin >> edg[i][0] >> edg[i][1] >> edg[i][2];
adj[edg[i][0]].pb({edg[i][1], i});
adj[edg[i][1]].pb({edg[i][0], i});
}
centroid_decomp(1, 0);
REP(i, LGN) {
st[i].reset(n + 1);
st[i].build(0, st[i].n, 1, arr[i]);
}
for(int i = 1; i <= n; i++) {
sort(all(cent_adj[i]));
for(auto &c : cent_adj[i]) {
int v = st[lv[i]].query(tin[c[0]][lv[i]], tin[c[0]][lv[i]] + ssz[c[0]][lv[i]] - 1);
cand[i].insert({v, c[0]});
c[1] = v;
}
cand[i].insert({0, -1});
cand[i].insert({0, -2});
cent_res[i] = (*cand[i].begin())[0] + (*next(cand[i].begin()))[0];
anss.insert({cent_res[i], i});
}
int last = 0;
REP(z, q) {
int d, e;
cin >> d >> e;
d = (d + last) % (n - 1);
e = (e + last) % w;
// cout << "d:" << d <<" e:" << e << "\n";
for(int i = 0; i < LGN; i++) {
if(edgnode[d][i] == -1) continue;
// cout << "level:" << i << "\n";
int node = edgnode[d][i];
int centr = cent[node][i];
int rep = comp[node][i];
auto itr = lower_bound(all(cent_adj[centr]), array<int, 2>({rep, 0}));
assert(rep == (*itr)[0]);
// cout << "node :" << node << " centr:" << centr << " rep:" << rep << " ";
cand[centr].erase({(*itr)[1], rep});
st[i].update(tin[node][i], tin[node][i] + ssz[node][i] - 1, e - edg[d][2]);
// cout << "old val: " << (*itr)[1] << " ";
(*itr)[1] = st[i].query(tin[rep][i], tin[rep][i] + ssz[rep][i] - 1);
// cout << "new val: " << (*itr)[1] << "\n";
cand[centr].insert({(*itr)[1], rep});
anss.erase({cent_res[centr], centr});
cent_res[centr] = (*cand[centr].begin())[0] + (*next(cand[centr].begin()))[0];
anss.insert({cent_res[centr], centr});
}
edg[d][2] = e;
// cout << "centro:" << (*anss.begin())[1] << " lvl:" << lv[(*anss.begin())[1]] << "\n";
last = (*anss.begin())[0];
cout << last << "\n";
}
}
signed main() {
fastio();
solve();
}
