#include <bits/stdc++.h>
using namespace std;
typedef long long int ll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
#define F first
#define S second
#define pb push_back
#define endl '\n'
#define Mp make_pair
#define all(x) x.begin(), x.end()
#define debug(x) cerr << #x << " = " << x << endl;
#define fast_io ios::sync_with_stdio(false);cin.tie(0);cout.tie(0);
#define file_io freopen("connect.in" , "r" , stdin) ; freopen("connect.out" , "w" , stdout);
ll mod = 1e9+7 ;
const int N = 1e5+23;
vector<pll> g[N];
int st[N], ft[N], tim, pos[N];
vector<pair<pll, ll> > E;
ll seg[4*N], lpz[4*N];
int n, q;
ll h[N];
ll ans[N];
pll di;
void dfs(int v, int p=0){
di=max(di, {h[v], v});
for (auto pp: g[v]){
ll u=pp.F, w=ans[pp.S];
if(u==p) continue;
h[u]=h[v]+w;
dfs(u, v);
}
}
int main()
{
fast_io
cin>>n>>q>>mod;
for (int i=0; i<n-1; i++){
ll u, v, w; cin>>v>>u>>w;
g[v].pb({u, i}); g[u].pb({v, i});
E.pb({{v, u}, w});
ans[i]=w;
}
ll la=0;
while(q--){
ll i, w;
cin>>i>>w;
i=(i+la)%(n-1);
w=(w+la)%mod;
ans[i]=w;
di={0, 0};
dfs(1);
int r=di.S;
h[r]=0;
di={0, 0};
dfs(r);
cout<<di.F<<endl;
la=di.F;
}
}
