#include <bits/stdc++.h>
#define speed ios_base::sync_with_stdio(0); cin.tie(0)
#define all(x) (x).begin(),(x).end()
#define F first
#define S second
//#pragma GCC optimize("O3,unroll-loops")
//#pragma GCC target("avx,avx2")
//#pragma GCC target("popcnt")
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef double db;
typedef long double ldb;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;
const ll MAX=2e5+10,P=1e9+7;
const ll INF=0x3f3f3f3f,oo=0x3f3f3f3f3f3f3f3f;
const ldb eps=1e-6;
const ldb PI=acos(-1.0);
const int dir[4][2]={{0,1},{0,-1},{1,0},{-1,0}};
template<typename T>
using vvector = vector<vector<T>>;
void dfs(int v,int p,ll dep,vvector<pll> &G,vector<ll> &ddp,vector<pll> &dfn) {
dfn[v].F=ddp.size();
ddp.push_back(dep);
for (auto [i,w]:G[v]) {
if (i==p) continue;
dfs(i,v,dep+w,G,ddp,dfn);
ddp.push_back(dep);
}
dfn[v].S=ddp.size()-1;
}
struct Node {
ll l,r;
ll ans;
ll la,ra;
ll mn,mx;
Node *lft,*rt;
ll lz;
void pu() {
ans = max({lft->ans,rt->ans,lft->ra+rt->mx,lft->mx+rt->la});
la = max({lft->la,rt->la,rt->mx-2*lft->mn});
ra = max({rt->ra,lft->ra,lft->mx-2*rt->mn});
mn = min(lft->mn,rt->mn);
mx = max(lft->mx,rt->mx);
}
void pd() {
lft->lz+=lz;
lft->la-=lz;
lft->ra-=lz;
lft->mx+=lz;
lft->mn+=lz;
rt->lz+=lz;
rt->la-=lz;
rt->ra-=lz;
rt->mx+=lz;
rt->mn+=lz;
lz=0;
}
Node(ll l,ll r,vector<ll> &ddp):l(l),r(r),lz(0){
if (l==r) {
ans=0;
la=-ddp[l];
ra=-ddp[l];
mn=ddp[l];
mx=ddp[l];
return;
}
ll mid=l+r>>1;
lft = new Node(l,mid,ddp);
rt = new Node(mid+1,r,ddp);
pu();
// cout<<l<<" "<<r<<" "<<ans<<" "<<la<<" "<<ra<<" "<<mx<<" "<<mn<<" lr ans lra mx mn\n";
}
void update(int L,int R,int val) {
if (L<=l and r<=R) {
lz+=val;
la-=val;
ra-=val;
mx+=val;
mn+=val;
return ;
}
pd();
int mid=l+r>>1;
if (L<=mid) lft->update(L,R,val);
if (R>=mid+1) rt->update(L,R,val);
pu();
}
};
int main() {
speed;
ll n,q,W;
cin>>n>>q>>W;
vvector<pll> G(n+1);
vector<pair<pll,ll>> E(n);
vector<ll> ddp;
vector<pll> dfn(n+1);
for (int i=1;i<=n-1;i++) {
ll a,b,w;
cin>>a>>b>>w;
E[i]={{a,b},w};
G[a].emplace_back(b,w);
G[b].emplace_back(a,w);
}
ddp.push_back(0);
dfs(1,0,0,G,ddp,dfn);
// for (int i=1;i<=2*n-1;i++) cout<<ddp[i]<<' ';
// cout<<"ddp\n";
Node *rt = new Node(1,2*n-1,ddp);
int last=0;
while (q--) {
ll d,e;
cin>>d>>e;
d = (d+last)%(n-1)+1;
e = (e+last)%W;
auto [a,b] = E[d].F;
if (dfn[a].F>dfn[b].F) swap(a,b);
rt->update(dfn[b].F,dfn[b].S,e-E[d].S);
E[d].S=e;
last=rt->ans;
cout<<last<<"\n";
}
return 0;
}
/*
10 10 10000
1 9 1241
5 6 1630
10 5 1630
2 6 853
10 1 511
5 3 760
8 3 1076
4 10 2051
7 10 40
*/
