#include<bits/stdc++.h>
using namespace std;
#define int long long
const int maxn = 2e5 + 5;
struct node{
int ans, mnsuf, mxpre, fsuf, fpre, fsum, sum;
} st[4 * maxn];
node merge(node a, node b){
return {max({a.ans, b.ans, -a.mnsuf + b.fpre, a.fsuf + b.mxpre}), min(b.mnsuf, b.sum + a.mnsuf), max(a.mxpre, a.sum + b.mxpre), max({-a.mnsuf + b.fsum, b.fsuf, a.fsuf + b.sum}), max({a.fsum + b.mxpre, a.fpre, -a.sum + b.fpre}), max({-a.sum + b.sum, -a.sum + b.fsum, a.fsum + b.sum}), a.sum + b.sum};
}
void update(int id, int l, int r, int p, int val){
if(l == r) st[id] = {abs(val),val,val,abs(val),abs(val),abs(val),val};
else{
int mid = (l + r) / 2;
if(p <= mid) update(id * 2, l, mid, p, val);
else update(id * 2 + 1, mid + 1, r, p, val);
st[id] = merge(st[id * 2], st[id * 2 + 1]);
}
}
vector<array<int, 2>> g[maxn];
int tin[maxn], out[maxn], timedfs;
int pos[maxn], len[maxn];
void dfs(int u, int p){
tin[u] = ++timedfs;
for(auto [v, id]: g[u]){
if(v == p) continue;
pos[id] = v;
dfs(v, u);
}
out[u] = ++timedfs;
}
signed main(){
ios_base::sync_with_stdio(false);
cin.tie(0); cout.tie(0);
int n, q, w; cin >> n >> q >> w;
for(int i = 1; i <= n - 1; i++){
int a, b, c; cin >> a >> b >> c;
g[a].push_back({b, i});
g[b].push_back({a, i});
len[i] = c;
}
dfs(1, 1);
for(int i = 1; i <= n - 1; i++){
update(1, 1, n * 2, tin[pos[i]], len[i]);
update(1, 1, n * 2, out[pos[i]],-len[i]);
}
int last = 0;
while(q--){
int d, e; cin >> d >> e;
d = (d + last) % (n - 1) + 1;
e = (e + last) % w;
update(1, 1, n * 2, tin[pos[d]], e);
update(1, 1, n * 2, out[pos[d]],-e);
cout << (st[1].ans) << "\n";
last = st[1].ans;
}
}
