#include<bits/stdc++.h>
using namespace std;
typedef long long LL;
const int N=(int)1e5;
const int MAXLOG=17;
#define ill pair<LL,int>
#define lef(id) id*2
#define rig(id) id*2+1
vector<int>ke[N+2];
int x[N+2],y[N+2];
LL c[N+2];
int n,q;
LL w;
void add_canh(int u,int v,int id){
ke[u].push_back(id) , ke[v].push_back(id);
return;
}
int sz[N+2]={},dep[N+2]={};
int sta[MAXLOG+2][N+2]={},fin[MAXLOG+2][N+2]={},time_dfs[MAXLOG+2]={};
int root[MAXLOG+2][N+2]={};
pair<LL,int> val[MAXLOG+2][N+2]={};
bool del[N+2]={};
struct Node{
LL mx1,mx2;
int color_1,color_2;
Node(){
mx1=mx2=color_1=color_2=0;
return;
}
void tang(LL x){
if (color_1!=0) mx1+=x;
if (color_2!=0) mx2+=x;
return;
}
LL F(){
LL sum=0;
sum=mx1+mx2;
return sum;
}
};
Node st[MAXLOG+2][N*4+2];
LL lazy[MAXLOG+2][N*4+2];
LL wanh[MAXLOG+2][N*4+2];
void upd(int dep,int id,int l,int r,int pos,LL val){
if (l>pos||r<pos) return ;
if (l==r) wanh[dep][id]=val;
else {
int m=(l+r)/2;
upd(dep,lef(id),l,m,pos,val);
upd(dep,rig(id),m+1,r,pos,val);
wanh[dep][id]=max(wanh[dep][lef(id)],wanh[dep][rig(id)]);
}
}
bool maximize(LL &a,LL b){
if (a<b) return a=b,true;
return false;
}
Node operator + (Node a,Node b){
LL mx=0;
Node res=Node();
maximize(mx,a.mx1) , maximize(mx,a.mx2) , maximize(mx,b.mx1) , maximize(mx,b.mx2);
if (mx==a.mx1) res.mx1=a.mx1,res.color_1=a.color_1;
if (mx==a.mx2) res.mx1=a.mx2,res.color_1=a.color_2;
if (mx==b.mx1) res.mx1=b.mx1,res.color_1=b.color_1;
if (mx==b.mx2) res.mx1=b.mx2,res.color_1=b.color_2;
mx=0;
if (a.color_1!=res.color_1) maximize(mx,a.mx1);
if (a.color_2!=res.color_1) maximize(mx,a.mx2);
if (b.color_1!=res.color_1) maximize(mx,b.mx1);
if (b.color_2!=res.color_1) maximize(mx,b.mx2);
if (a.color_1!=res.color_1 && a.mx1==mx) res.mx2=a.mx1,res.color_2=a.color_1;
if (a.color_2!=res.color_1 && a.mx2==mx) res.mx2=a.mx2,res.color_2=a.color_2;
if (b.color_1!=res.color_1 && b.mx1==mx) res.mx2=b.mx1,res.color_2=b.color_1;
if (b.color_2!=res.color_1 && b.mx2==mx) res.mx2=b.mx2,res.color_2=b.color_2;
return res;
}
void build_tang(int tang,int id=1,int l=1,int r=n){
if (l==r) {
st[tang][id]=Node();
st[tang][id].mx1=val[tang][l].first;
st[tang][id].color_1=val[tang][l].second;
return;
}
else {
int m=(l+r)/2;
build_tang(tang,lef(id),l,m);
build_tang(tang,rig(id),m+1,r);
st[tang][id]=st[tang][lef(id)]+st[tang][rig(id)];
}
}
void pushdown(int tang,int id){
LL &x=lazy[tang][id];
lazy[tang][lef(id)]+=x , lazy[tang][rig(id)]+=x;
st[tang][lef(id)].tang(x) , st[tang][rig(id)].tang(x);
x=0;
return;
}
void upd(int tang,int id,int l,int r,int u,int v,LL add){
if (l>v||r<u) return;
if (u<=l&&r<=v) {
st[tang][id].tang(add);
lazy[tang][id]+=add;
return;
}
int m=(l+r)/2;
pushdown(tang,id);
upd(tang,lef(id),l,m,u,v,add);
upd(tang,rig(id),m+1,r,u,v,add);
st[tang][id]=st[tang][lef(id)]+st[tang][rig(id)];
return;
}
Node Get(int tang,int id,int l,int r,int u,int v){
if (l>v||r<u) return Node();
if (u<=l&&r<=v) return st[tang][id];
int m=(l+r)/2;
pushdown(tang,id);
return Get(tang,lef(id),l,m,u,v)+Get(tang,rig(id),m+1,r,u,v);
}
namespace Wanh{
void pre_dfs(int u,int p){
sz[u]=1;
for(auto&id:ke[u]){
int v=u^x[id]^y[id];
if (del[v]||v==p) continue;
pre_dfs(v,u);
sz[u]+=sz[v];
}
return;
}
int Find_centroid(int u,int p,int half){
for(auto&id:ke[u]){
int v=u^x[id]^y[id];
if (v==p||del[v]) continue;
if (sz[v]>half) return Find_centroid(v,u,half);
}
return u;
}
void dfs_build(int dep,int u,int p,int Faker,int cur_color,LL cost=0){
sta[dep][u]=++time_dfs[dep];
root[dep][u]=Faker;
val[dep][sta[dep][u]]={cost,cur_color};
int cur=cur_color;
for(auto&id:ke[u]){
int v=u^x[id]^y[id];
if (v==p||del[v]) continue;
if (cur_color==0) ++cur;
dfs_build(dep,v,u,Faker,cur,cost+c[id]);
}
fin[dep][u]=time_dfs[dep];
}
void build(int u,int p){
pre_dfs(u,u);
u=Find_centroid(u,u,sz[u]/2);
del[u]=true;
dep[u]=dep[p]+1;
dfs_build(dep[u],u,u,u,0);
for(auto&id:ke[u]){
int v=u^x[id]^y[id];
if (del[v]) continue;
build(v,u);
}
return;
}
}
using namespace Wanh;
void modify(int dep,int u,int v,LL cost){
if (sta[dep][u]<sta[dep][v]) swap(u,v);
int l=sta[dep][u],r=fin[dep][u];
upd(dep,1,1,time_dfs[dep],l,r,cost);
}
void change_canh(int u,int v,LL cost){
for(int i=min(dep[u],dep[v]);i>=1;--i) {
int r=root[i][u];
modify(i,u,v,cost);
LL k=Get(i,1,1,time_dfs[i],sta[i][r],fin[i][r]).F();
upd(i,1,1,time_dfs[i],sta[i][r],k);
}
return;
}
LL duongkinh(){
LL ans=0;
for(int i=1;i<=MAXLOG && time_dfs[i]>0;++i) ans=max(ans,wanh[i][1]);
return ans;
}
int main(){
ios::sync_with_stdio(false);
cin.tie(0) ; cout.tie(0);
#define name "main"
if (fopen(name".inp","r")){
freopen(name".inp","r",stdin);
freopen(name".out","w",stdout);
}
cin>>n>>q>>w;
for(int i=0;i<n-1;++i) {
cin>>x[i]>>y[i]>>c[i];
add_canh(x[i],y[i],i);
}
build(1,0);
for(int i=1;i<=MAXLOG && time_dfs[i];++i) build_tang(i,1,1,time_dfs[i]);
for(int i=1;i<=n;++i) {
LL k=Get(dep[i],1,1,time_dfs[dep[i]],sta[dep[i]][i],fin[dep[i]][i]).F();
upd(dep[i],1,1,time_dfs[dep[i]],sta[dep[i]][i],k);
}
LL last=0;
while(q--){
int d;
LL e; cin>>d>>e;
d=(last+d)%(n-1) , e=(last+e)%w;
int change_cost=e-c[d];
c[d]+=change_cost;
change_canh(x[d],y[d],change_cost);
LL ans=duongkinh();
cout<<ans<<'\n';
last=ans;
}
}
