#include <bits/stdc++.h>
#define all(x) (x).begin(), (x).end()
#define ff first
#define ss second
#define pb push_back
#define mp make_pair
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef long double ld;
typedef pair<ll, ll> pll;
typedef pair<ull, ull> pull;
typedef pair<int, int> pii;
typedef pair<ld, ld> pld;
struct tree{
vector<ll> seg;
vector<ll> lazy;
int maxn;
void init(int n){
maxn = n-1;
seg.resize(4*n);
lazy.resize(4*n);
}
void push(int v){
seg[2*v] += lazy[v];
seg[2*v+1] += lazy[v];
lazy[2*v] += lazy[v];
lazy[2*v+1] += lazy[v];
lazy[v] = 0;
}
void upd(int v, int tl, int tr, int l, int r, ll val){
if(r < tl || tr < l)
return;
if(l <= tl && tr <= r){
seg[v] += val;
lazy[v] += val;
}
else{
push(v);
upd(2*v, tl, (tl+tr)/2, l, r, val);
upd(2*v+1, (tl+tr)/2+1, tr, l, r, val);
seg[v] = max(seg[2*v], seg[2*v+1]);
}
}
ll get(int v, int tl, int tr, int l, int r){
if(r < tl || tr < l)
return -1e18;
if(l <= tl && tr <= r){
return seg[v];
}
else{
push(v);
return max(
get(2*v, tl, (tl+tr)/2, l, r),
get(2*v+1, (tl+tr)/2+1, tr, l, r));
}
}
};
struct edge{
ll x, y, z;
};
vector<pii> g[100009];
edge e[100009];
int sz[100009];
int block[100009];
void findsz(int v, int prt){
sz[v] = 1;
for(auto u : g[v]){
if(block[u.ff] || u.ff == prt) continue;
findsz(u.ff, v);
sz[v] += sz[u.ff];
}
}
int findcentroid(int v, int prt, int totsz){
for(auto u : g[v]){
if(block[u.ff] || u.ff == prt) continue;
if(sz[u.ff]*2 > totsz)
return findcentroid(u.ff, v, totsz);
}
return v;
}
int curtime = 0;
int root;
vector<pii> tin[100009];
vector<int> tout[100009];
vector<int> change[100009];
vector<pii> entry[100009];
set<pair<ll, pll>, greater<pair<ll, pll>>> centmax[100009];
ll centans[100009];
tree seg[100009];
set<pll, greater<pll>> totmax;
void dfs(int v, int prt){
int mytime = curtime++;
tin[root].pb({v, mytime});
ll distoprt;
for(auto u : g[v]){
if(block[u.ff])
continue;
if(u.ff == prt){
change[u.ss].pb(root);
distoprt = e[u.ss].z;
continue;
}
dfs(u.ff, v);
}
tout[root][mytime] = curtime-1;
seg[root].upd(1, 0, seg[root].maxn, mytime, curtime-1, distoprt);
}
void decomp(){
findsz(root, 0);
int totsz = sz[root];
root = findcentroid(root, 0, totsz);
seg[root].init(totsz);
tin[root].pb({root, -1});
tout[root].resize(totsz);
curtime = 0;
for(auto u : g[root]){
if(block[u.ff]) continue;
int enter = curtime;
dfs(u.ff, root);
entry[root].pb({enter, curtime-1});
centmax[root].insert({seg[root].get(1, 0, seg[root].maxn, enter, curtime-1), {enter, curtime-1}});
}
sort(all(tin[root]));
if(centmax[root].empty()) return;
auto it = centmax[root].begin();
centans[root] = it->ff;
if(centmax[root].size() >= 2){
++it;
centans[root] += it->ff;
}
totmax.insert({centans[root], root});
block[root] = 1;
int v = root;
for(auto u : g[v]){
if(block[u.ff]) continue;
root = u.ff;
decomp();
}
}
ll n, q, w;
ll last = 0;
int main() {
ios_base::sync_with_stdio(false);
cin.tie(nullptr);
//freopen("in.txt", "r", stdin);
//freopen("out.txt", "w", stdout);
cin >> n >> q >> w;
for(int i = 0; i < n-1; ++i){
cin >> e[i].x >> e[i].y >> e[i].z;
g[e[i].x].pb({e[i].y, i});
g[e[i].y].pb({e[i].x, i});
}
root = 1;
decomp();
for(int i = 0; i < q; ++i){
ll d, val;
cin >> d >> val;
d = (d+last)%(n-1);
val = (val+last)%w;
ll ch = val - e[d].z;
for(auto root : change[d]){
int v;
if(lower_bound(all(tin[root]), mp((int)e[d].x, -1))->ss > lower_bound(all(tin[root]), mp((int)e[d].y, -1))->ss)
v = e[d].x;
else
v = e[d].y;
//cout << v << ' ' << root << '\n';
int in = lower_bound(all(tin[root]), mp(v, -1))->ss;
int out = tout[root][in];
pii cursub = entry[root][upper_bound(all(entry[root]), mp(in, (int)1e9))-entry[root].begin()-1];
centmax[root].erase({seg[root].get(1, 0, seg[root].maxn, cursub.ff, cursub.ss), cursub});
seg[root].upd(1, 0, seg[root].maxn, in, out, ch);
centmax[root].insert({seg[root].get(1, 0, seg[root].maxn, cursub.ff, cursub.ss), cursub});
totmax.erase({centans[root], root});
auto it = centmax[root].begin();
centans[root] = it->ff;
if(centmax[root].size() >= 2){
++it;
centans[root] += it->ff;
}
totmax.insert({centans[root], root});
}
last = totmax.begin()->ff;
cout << last << '\n';
e[d].z = val;
}
}
