#include <bits/stdc++.h>
#pragma GCC optimize("O3,no-stack-protector,unroll-loops")
#pragma GCC target("avx2,fma")
#define rep(i,l,r) for (int i = l; i < r; i++)
#define repr(i,r,l) for (int i = r; i >= l; i--)
#define X first
#define Y second
#define pb push_back
#define endl '\n'
#define debug(x) cerr << #x << " : " << x << endl;
using namespace std;
typedef long long ll;
typedef long double ld;
typedef pair<int,int> pll;
typedef pair<long double,long double> pld;
const long long int N = 1e5+10,mod = 1e9+7,inf = 1e9,sq = 700,sig = 26;
inline int mkay(int a,int b){
if (a+b >= mod) return a+b-mod;
if (a+b < 0) return a+b+mod;
return a+b;
}
inline int poww(int n,int k){
int c = 1;
while (k){
if (k&1) c = (1ll*c*n)%mod;
n = (1ll*n*n)%mod;
k >>= 1;
}
return c;
}
vector<pll> adj[N];
int e[N],seg[N*4];
pll E[N];
int dp[N],n;
void dfs(int v){
for (pll u : adj[v]){
dfs(u.X);
dp[v] = max(dp[v],dp[u.X]+e[u.Y]);
}
}
void build(int l,int r,int v){
if (r-l == 1){
for (pll u : adj[l]) seg[v] += dp[u.X]+e[u.Y];
return;
}
int m = (l+r) >> 1;
build(l,m,2*v);
build(m,r,2*v+1);
seg[v] = max(seg[2*v],seg[2*v+1]);
}
void upd(int l,int r,int v,int p){
if (r-l == 1){
seg[v] = 0;
for (pll u : adj[l])
seg[v] += dp[u.X]+e[u.Y];
return;
}
int m = (l+r) >> 1, u = (v << 1);
if (p < m) upd(l,m,u,p);
else upd(m,r,u+1,p);
seg[v] = max(seg[u|1],seg[u]);
}
int main(){
ios :: sync_with_stdio(0); cin.tie(0);cout.tie(0);
int q;
ll w;
cin >> n >> q >> w;
rep(i,0,n-1){
int u,v;
ll d;
cin >> u >> v >> d;
e[i] = d;
if (u > v) swap(u,v);
E[i] = {u,v};
adj[u].pb({v,i});
}
ll last = 0;
dfs(1);
build(1,n+1,1);
while (q--){
int d;
ll x;
cin >> d >> x;
d = (d+last)%(n-1);
x = (x+last)%w;
e[d] = x;
int v = E[d].X;
while (v){
dp[v] = 0;
for (pll u : adj[v])
dp[v] = max(dp[v],dp[u.X]+e[u.Y]);
upd(1,n+1,1,v);
v >>= 1;
}
last = seg[1];
cout << last << endl;
}
return 0;
}
