#include<bits/stdc++.h>
using namespace std;
const int maxn=100000+10;
struct yal{
int u,v,par;
long long w;
yal(){
u=v=par=w=0;
}
int getad(int fu){
int ret=(fu^u^v);
return ret;
}
};
yal alled[maxn];
int kaf=(1<<18),lastc[maxn],vala[maxn],fake,timea=0,n,q,sz[maxn],parh[maxn],par[maxn],childh[maxn];
long long w;
vector<int>adj[maxn],adja[maxn];
pair<int,int>stf[maxn];
bool cmp(int a,int b){
return sz[alled[a].getad(fake)]>sz[alled[b].getad(fake)];
}
void dfs1(int u,int bala=0){
//cout<<u<<" "<<bala<<endl;
sz[u]=1;
par[u]=bala;
for(auto x:adj[u]){
int v=alled[x].getad(u);
//cout<<u<<" "<<v<<"\n";
if(v!=bala){
alled[x].par=u;
dfs1(v,u);
adja[u].push_back(x);
sz[u]+=sz[v];
}
}
swap(adj[u],adja[u]);
fake=u;
sort(adj[u].begin(),adj[u].end(),cmp);
}
void calh(int u,int balah=1){
//cout<<u<<" "<<balah<<"\n";
timea++;
vala[timea]=u;
stf[u].first=timea;
parh[u]=balah;
//if(u==1)
// {
// parh[u]=0;
//}
if(adj[u].size()==0){
lastc[u]=u;
stf[u].second=timea;
return ;
}
int v=alled[adj[u][0]].getad(u);
//cout<<u<<" "<<v<<"\n";
calh(v,balah);
lastc[u]=lastc[v];
childh[u]=v;
for(int i=1;i<(int)adj[u].size();i++){
v=alled[adj[u][i]].getad(u);
if(v!=par[u]){
calh(v,v);
}
}
stf[u].second=timea;
}
struct node{
int w;
long long maxa,lazy;
node(){
w=maxa=lazy=0;
}
};
struct segment{
node seg[(1<<19)];
void build(int i){
if(i>=kaf){
seg[i].w=i-kaf;
return ;
}
build((i<<1));
build((i<<1)^1);
seg[i].w=seg[(i<<1)].w;
}
node merge(node a,node b){
a.maxa+=a.lazy;
b.maxa+=b.lazy;
a.lazy=0;
b.lazy=0;
if(a.maxa>=b.maxa){
return a;
}
return b;
}
void calc(int i){
if((i<<1)>=(1<<19)){
return ;
}
node f=merge(seg[(i<<1)],seg[(i<<1)^1]);
seg[i].maxa=f.maxa;
seg[i].w=f.w;
}
void shift(int i){
if((i<<1)>=(1<<19)||seg[i].lazy==0){
return ;
}
seg[(i<<1)].lazy+=seg[i].lazy;
seg[(i<<1)^1].lazy+=seg[i].lazy;
seg[i].lazy=0;
calc(i);
}
void upd(int i,int l,int r,int tl,int tr,long long w){
if(l>r||l>tr||r<tl){
return ;
}
shift(i);
if(l>=tl&&r<=tr){
// cout<<l<<" "<<r<<" "<<w<<"\n";
seg[i].lazy+=w;
return ;
}
int m=(l+r)>>1;
upd((i<<1),l,m,tl,tr,w);
upd((i<<1)^1,m+1,r,tl,tr,w);
calc(i);
}
void upd2(int i,int l,int r,int tl,int tr,long long w){
if(l>r||l>tr||r<tl){
return ;
}
shift(i);
if(l>=tl&&r<=tr){
// cout<<l<<" "<<r<<" "<<w<<"\n";
seg[i].lazy=w;
seg[i].maxa=0;
return ;
}
int m=(l+r)>>1;
upd2((i<<1),l,m,tl,tr,w);
upd2((i<<1)^1,m+1,r,tl,tr,w);
calc(i);
}
node pors(int i,int l,int r,int tl,int tr){
if(l>r||l>tr||r<tl){
node nn;
return nn;
}
shift(i);
if(l>=tl&&r<=tr){
// cout<<l<<" "<<r<<" "<<seg[i].maxa<<" "<<seg[i].lazy<<" "<<seg[i].w<<" tof\n";
return seg[i];
}
int m=(l+r)>>1;
node ret=merge(pors((i<<1),l,m,tl,tr),pors((i<<1)^1,m+1,r,tl,tr));
return ret;
}
}seg,seg2;
void update(int i)
{
i=parh[i];
i=par[i];
if(i==0){
return ;
}
node l=seg.pors(1,0,kaf-1,stf[i].first,stf[childh[i]].first-1);
node r=seg.pors(1,0,kaf-1,stf[childh[i]].second+1,stf[i].second);
node rr=seg.pors(1,0,kaf-1,stf[i].first,stf[i].first);
long long wtf=max(l.maxa+l.lazy,r.maxa+r.lazy)-(rr.maxa+rr.lazy)*2;
// cout<<i<<" "<<wtf<<" "<<(rr.maxa+rr.lazy)<<" asd \n";
seg2.upd2(1,0,kaf-1,stf[i].first,stf[i].first,wtf);
update(i);
}
long long pors(int i,long long w){
node boro=seg2.pors(1,0,kaf-1,stf[parh[i]].first,stf[i].first-1);
long long ret=boro.maxa+boro.lazy+w;
//cout<<boro.maxa+boro.lazy<<" "<<vala[boro.w]<<" "<<w<<" asda "<<endl;
// cout<<i<<" "<<parh[i]<<" ";
i=parh[i];
if(par[i]==0){
ret=max(ret,w);
// cout<<ret<<'\n';
return ret;
}
node l=seg.pors(1,0,kaf-1,stf[par[i]].first,stf[i].first-1);
node r=seg.pors(1,0,kaf-1,stf[i].second+1,stf[par[i]].second);
node rr=seg.pors(1,0,kaf-1,stf[par[i]].first,stf[par[i]].first);
long long reta=max(l.maxa+l.lazy,r.maxa+r.lazy)-(rr.maxa+rr.lazy)*2+w;
//cout<<ret<<" "<<reta<<"\n";
ret=max(ret,reta);
i=par[i];
if(i==0){
return ret;
}
ret=max(ret,pors(i,w));
return ret;
}
int main(){
ios::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
cin>>n>>q>>w;
for(int i=0;i<n-1;i++){
cin>>alled[i].u>>alled[i].v>>alled[i].w;
adj[alled[i].u].push_back(i);
adj[alled[i].v].push_back(i);
}
//cout<<"salam"<<endl;
dfs1(1);
//cout<<"salam2"<<endl;
calh(1);
//cout<<"salam3"<<endl;
seg.build(1);
seg2.build(1);
//cout<<"salam"<<endl;
for(int i=0;i<n-1;i++){
int v=alled[i].getad(alled[i].par);
//cout<<v<<" "<<alled[i].w<<"\n";
//cout<<stf[v].first<<" "<<stf[v].second<<" "<<alled[i].w<<'\n';
seg.upd(1,0,kaf-1,stf[v].first,stf[v].second,alled[i].w);
}
for(int i=1;i<=n;i++){
if((int)adj[i].size()==0){
continue;
}
node l=seg.pors(1,0,kaf-1,stf[i].first,stf[childh[i]].first-1);
node r=seg.pors(1,0,kaf-1,stf[childh[i]].second+1,stf[i].second);
node rr=seg.pors(1,0,kaf-1,stf[i].first,stf[i].first);
long long wtf=max(l.maxa+l.lazy,r.maxa+r.lazy)-(rr.maxa+rr.lazy)*2;
//cout<<i<<" "<<wtf<<" "<<(rr.maxa+rr.lazy)<<"\n";
seg2.upd2(1,0,kaf-1,stf[i].first,stf[i].first,wtf);
}
long long lasta=0;
for(int i=0;i<q;i++){
long long we,e;
cin>>e>>we;
e+=lasta;
we+=lasta;
e%=n-1;
we%=w;
//cout<<e<<" "<<we<<" "<<alled[e].w<<"\n";
//cout<<e<<" "<<we<<"\n";
int v=alled[e].getad(alled[e].par);
//cout<<"upd "<<v<<"\n";
seg.upd(1,0,kaf-1,stf[v].first,stf[v].second,-alled[e].w);;
seg2.upd(1,0,kaf-1,stf[v].first,stf[v].second,+alled[e].w);
alled[e].w=we;
seg.upd(1,0,kaf-1,stf[v].first,stf[v].second,alled[e].w);
seg2.upd(1,0,kaf-1,stf[v].first,stf[v].second,-alled[e].w);
update(v);
v=vala[seg.seg[1].w];
node nn=seg.pors(1,0,kaf-1,stf[v].first,stf[v].second);
lasta=pors(v,nn.maxa+nn.lazy);
//cout<<v<<" "<<nn.maxa+nn.lazy<<"\n";
cout<<lasta<<"\n";
}
}
