//Bismillahirrahmanirrahim
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#include <bits/stdc++.h>
using namespace std;
typedef long long lo;
typedef pair< lo,lo > PII;
typedef pair< lo,PII > PIII;
#define fi first
#define se second
#define mp make_pair
#define int long long
#define endl "\n"
#define pb push_back
#define fio() ios_base::sync_with_stdio(false);cin.tie(NULL);cout.tie(NULL)
#define FOR for(int i=1;i<=n;i++)
#define mid ((start+end)/2)
#define ort ((bas+son)/2)
const lo inf = 1000000000000000000;
const lo KOK = 100000;
const lo LOG = 30;
const lo li = 100005;
const lo mod = 1000000007;
int n,m,b[li],a[li],k,t,x[li],y[li],z[li],mx,ind,dep[li],st[li],en[li],lazy[li*4],say,hedef,parca[li],indis[li];
int cev;
PIII tree[li*4];
multiset<int> stt;
string s;
vector<PII> v[li];
inline void dfs(int node,int ata,int der){
for(int i=0;i<(int)v[node].size();i++){
int go=v[node][i].fi;
int co=v[node][i].se;
if(go==ata)continue;
dfs(go,node,der+co);
}
if(der>mx)ind=node;
mx=max(mx,der);
dep[node]=der;
}
inline void dfs1(int node,int ata){
int flag=0;
if(ata==1)parca[node]=node;
else if(node!=1)parca[node]=parca[ata];
for(int i=0;i<(int)v[node].size();i++){
int go=v[node][i].fi;
if(go==ata)continue;
dfs1(go,node);
flag=1;
if(st[node]==0)st[node]=st[go];
else st[node]=min(st[node],st[go]);
en[node]=max(en[node],en[go]);
}
if(flag==0){
st[node]=++say;
indis[say]=node;
en[node]=say;
}
}
inline void build(int node,int start,int end){
if(start==end){tree[node]={dep[indis[start]],{start,parca[indis[start]]}};return ;}
build(node*2,start,mid),build(node*2+1,mid+1,end);
tree[node]=max(tree[node*2],tree[node*2+1]);
}
inline void push(int node,int start,int end){
if(lazy[node]==0)return ;
tree[node].fi+=lazy[node];
if(start!=end){
lazy[node*2]+=lazy[node];
lazy[node*2+1]+=lazy[node];
}
lazy[node]=0;
}
inline void update(int node,int start,int end,int l,int r,int val){
push(node,start,end);
if(start>end || start>r || end<l)return ;
if(start>=l && end<=r){
lazy[node]=val;
push(node,start,end);
return ;
}
update(node*2,start,mid,l,r,val),update(node*2+1,mid+1,end,l,r,val);
tree[node]=max(tree[node*2],tree[node*2+1]);
}
inline PIII query(int node,int start,int end,int l,int r){
if(start>end || start>r || end<l)return {0,{0,0}};
push(node,start,end);
if(start>=l && end<=r)return tree[node];
return max(query(node*2,start,mid,l,r),query(node*2+1,mid+1,end,l,r));
}
int32_t main(void){
//~ freopen("at.txt","r",stdin);
//~ freopen("att.txt","w",stdout);
scanf("%lld %lld %lld",&n,&t,&k);
int yes=0;
for(int i=1;i<n;i++){
scanf("%lld %lld %lld",&x[i],&y[i],&z[i]);
stt.insert(z[i]);
if(x[i]==1)yes++;
if(y[i]==1)yes++;
}
if(n*t<=5000*5000){
while(t--){
int d,e;
scanf("%lld %lld",&d,&e);
z[(d+cev)%(n-1)+1]=(cev+e)%k;
FOR v[i].clear();
for(int i=1;i<n;i++){
v[x[i]].pb({y[i],z[i]});
v[y[i]].pb({x[i],z[i]});
}
mx=0;
dfs(1,0,0);
mx=0;
dfs(ind,0,0);
cev=mx;
printf("%lld\n",cev);
}
return 0;
}
if(yes==n-1){
while(t--){
int d,e;
scanf("%lld %lld",&d,&e);
stt.erase(stt.find(z[(d+cev)%(n-1)+1]));
z[(d+cev)%(n-1)+1]=(cev+e)%k;
stt.insert(z[(d+cev)%(n-1)+1]);
auto it=stt.end();
if(it==stt.begin()){cev=0;printf("%lld\n",cev);continue;}
it--;
cev=*it;
if(it==stt.begin()){printf("%lld\n",cev);continue;}
it--;
cev+=*it;
printf("%lld\n",cev);
}
return 0;
}
for(int i=1;i<n;i++){
v[x[i]].pb({y[i],z[i]});
v[y[i]].pb({x[i],z[i]});
}
dfs(1,0,0);
dfs1(1,0);
build(1,1,say);
//~ cout<<say<<endl;
while(t--){
int d,e;
scanf("%lld %lld",&d,&e);
if(dep[y[(d+cev)%(n-1)+1]]<dep[x[(d+cev)%(n-1)+1]])swap(x[(d+cev)%(n-1)+1],y[(d+cev)%(n-1)+1]);
update(1,1,say,st[y[(d+cev)%(n-1)+1]],en[y[(d+cev)%(n-1)+1]],-z[(d+cev)%(n-1)+1]+((cev+e)%k));
z[(d+cev)%(n-1)+1]=(cev+e)%k;
//~ update(1,1,say,st[y[(d+cev)%(n-1)+1]],en[y[(d+cev)%(n-1)+1]],z[(d+cev)%(n-1)+1]);
PIII at=query(1,1,say,1,say);
cev=at.fi;
int mxx=0;
//~ cout<<say<<" : : "<<at.se.se<<" : : "<<st[at.se.se]<<" : : "<<en[at.se.se]<<endl;
if(st[at.se.se]>1)mxx=max(mxx,query(1,1,say,1,st[at.se.se]-1).fi);
if(en[at.se.se]<say)mxx=max(mxx,query(1,1,say,en[at.se.se]+1,say).fi);
cev+=mxx;
printf("%lld\n",cev);
}
return 0;
}
