#include<bits/stdc++.h>
using namespace std;
#define int long long
const int N=1e5+10;
int n,q,w;
int ea[N],eb[N],ec[N];
namespace satt{
	struct node{
		int fa,son[3],d,l,r,s,rta;
	}tr[N<<2];int tot;
	#define fa(k) tr[k].fa
	#define ls(k) tr[k].son[0]
	#define rs(k) tr[k].son[1]
	#define ms(k) tr[k].son[2]
	#define ta(k) tr[k].rta
	void pushup(int x,int ty){
		if(!x)return;
		if(ty==0){
			if(x>n){tr[x].d=tr[x].s=tr[x].l=tr[x].r=ec[x-n];return;}
			tr[x].s=tr[ls(x)].s+tr[rs(x)].s;
			tr[x].d=tr[ls(x)].r+tr[rs(x)].l;
			tr[x].d=max({tr[x].d,tr[ls(x)].d,tr[rs(x)].d,tr[ms(x)].d});
			tr[x].d=max(tr[x].d,max(tr[ls(x)].r,tr[rs(x)].l)+tr[ms(x)].l);
			tr[x].l=max(tr[ls(x)].l,tr[ls(x)].s+max(tr[rs(x)].l,tr[ms(x)].l));
			tr[x].r=max(tr[rs(x)].r,tr[rs(x)].s+max(tr[ls(x)].r,tr[ms(x)].l));
		}
		else{
			tr[x].d=tr[ls(x)].l+tr[rs(x)].l;
			tr[x].d=max({tr[x].d,tr[ls(x)].d,tr[rs(x)].d,tr[ms(x)].d});
			tr[x].d=max(tr[x].d,tr[ms(x)].l+max(tr[ls(x)].l,tr[rs(x)].l));
			tr[x].l=max({tr[ls(x)].l,tr[rs(x)].l,tr[ms(x)].l});tr[x].r=tr[x].l;
		}
	}
	void pushrev(int x){
		if(!x)return;
		swap(ls(x),rs(x));
		swap(tr[x].l,tr[x].r);
		ta(x)^=1;
	}
	void pushdown(int x,int ty){
		if(!ta(x)||!x)return;
		ta(x)=0;pushrev(ls(x)),pushrev(rs(x));
		pushup(x,ty);
	}
	bool isr(int x){return (x!=ls(fa(x))&&x!=rs(fa(x)));}
	void pushall(int x,int ty){
		if(!x)return;
		if(!isr(x))pushall(fa(x),ty);
		pushdown(x,ty);
	}
	bool dir(int x){return rs(fa(x))==x;}
	void rotate(int x,int ty){
		int y=fa(x),z=fa(y),w=dir(x);
		fa(x)=z;
		if(z)tr[z].son[ms(z)==y?2:dir(y)]=x;
		tr[y].son[w]=tr[x].son[w^1];
		if(tr[x].son[w^1])tr[tr[x].son[w^1]].fa=y;
		tr[x].son[w^1]=y;fa(y)=x;
		pushup(y,ty),pushup(x,ty);
		if(!isr(x))pushup(z,ty);
		else pushup(z,ty^1);
	}
	void splay(int x,int ty,int goal=0){
		pushall(x,ty);
		while(fa(x)!=goal&&!isr(x)){
			int y=fa(x);
			if(fa(y)!=goal&&!isr(y))rotate(dir(x)^dir(y)?x:y,ty);
			rotate(x,ty);
		}
	}
	void setf(int x,int y,int w){
		if(y)tr[y].son[w]=x;
		if(x)fa(x)=y;
	}
	int rub[N],rtop;int nw(){if(rtop)return rub[rtop--];return ++tot;}
	void Del(int x){
		if(!x)return;
		tr[x].fa=tr[x].son[0]=tr[x].son[1]=tr[x].son[2]=0;
		tr[x].l=tr[x].r=tr[x].d=tr[x].s=tr[x].rta=0;rub[++rtop]=x;
	}
	void del(int x){
		if(ls(x)){
			int p=ls(x);pushdown(p,1);
			while(rs(p))p=rs(p),pushdown(p,1);
			splay(p,1,x);setf(rs(x),p,1);setf(p,fa(x),2);
			pushup(p,1);pushup(fa(x),0);
		}
		else{setf(rs(x),fa(x),2);}
		Del(x);
	}
	void splice(int x){
		splay(x,0);
		if(!fa(x))return;
		int y=fa(x);splay(y,1);
		int z=fa(y);splay(z,0);
		pushdown(y,1);
		if(rs(z)){
			swap(fa(x),fa(rs(z)));
			swap(ms(y),rs(z));
			pushup(y,1),pushup(z,0);
		}
		else{
			setf(x,z,1);ms(y)=0;
			del(y);pushup(z,0);
		}
	}
	void access(int x){
		splay(x,0);
		if(rs(x)){
			int p=nw();
			setf(ms(x),p,0);
			setf(rs(x),p,2);
			rs(x)=0;setf(p,x,2);
			pushup(p,1),pushup(x,0);
		}
		int y=x;
		while(fa(x)){
			splice(x);x=fa(x);pushup(x,0);
		}
		splay(y,0);
	}
	void mkr(int x){access(x),pushrev(x);}
	void link(int x,int y,int z){
		access(x),mkr(y);
		setf(y,x,1),setf(z,y,0);
		pushup(z,0),pushup(y,0),pushup(x,0);
	}
	void expos(int x,int y){mkr(y);access(x);}
	void write(){
		cout<<tot<<endl;
		for(int i=1;i<=tot;i++){
			cout<<i<<":"<<ls(i)<<" "<<ms(i)<<" "<<rs(i)<<' '<<fa(i)<<"  "<<tr[i].rta<<"  "<<tr[i].s<<" "<<tr[i].d<<" "<<tr[i].l<<" "<<tr[i].r<<endl;
		}
	}
}
signed main(){
	scanf("%lld%lld%lld",&n,&q,&w);satt::tot=n*2-1;
	for(int i=1;i<n;i++){
		scanf("%lld%lld%lld",&ea[i],&eb[i],&ec[i]);
		satt::link(ea[i],eb[i],i+n);
	}
	satt::mkr(1);
	// for(int i=1;i<=n;i++)satt::splay(i,0);
	// satt::write();
	// for(int i=1;i<=n;i++){
	// 	satt::splay(i,0);
	// 	satt::write();
	// }
	int ans=0;
	while(q--){
		int x,y;scanf("%lld%lld",&x,&y);
		x=(x+ans)%(n-1),y=(y+ans)%w;x++;
		// cout<<ea[x]<<" "<<eb[x]<<endl;
		satt::expos(ea[x],eb[x]);
		ec[x]=y;
		satt::pushup(x+n,0);
		satt::pushup(eb[x],0);satt::pushup(ea[x],0);
		ans=satt::tr[ea[x]].d;
		cout<<ans<<endl;
		// satt::write();
	}
	return 0;
}
/*
g++ 1.cpp -o 1 -std=c++14 -O2 -Wall 
./1


10 1 10000
7 2 9990
7 4 2933
6 9 131
2 5 4180
10 8 6036
2 10 8488
6 1 4703
8 3 6095
10 9 4297
7 1009

10 10 10
1 2 1
1 3 7
3 4 1
2 5 5
4 6 4
3 7 3
6 8 5
8 9 8
6 10 4
9 8
7 8
1 3
7 4
9 2
7 4
3 3
5 7
2 8
2 8

31
34
36
32
32
32
34
37
38
38
*/