#include<bits/stdc++.h>
#define ll long long
#define pb push_back
#define F first
#define S second
#define coy cout<<"YES\n"
#define con cout<<"NO\n"
#define co1 cout<<"-1\n"
#define sc(x) scanf("%lld",&x)
#define all(x) x.begin(),x.end()
#define fast ios::sync_with_stdio(0);cin.tie(0);cout.tie(0);
using namespace std;
const int SI=3e5+7;
ll INF=8e18+7;
int dx[] = {1 , -1 , 0 , 0};
int dy[] = {0 , 0 , 1 , -1};
int MOD=1e9+7;
ll n,q,w,last,len[SI];
ll vis[SI],c,ans;
vector < pair < ll,ll> > v[SI];
void dfs(int node,ll dep)
{
vis[node]=c;
ans=max(ans,dep);
for (auto i:v[node])
{
if (vis[i.F]==c)
continue ;
dfs(i.F,dep+len[i.S]);
}
}
void DFS()
{
for (int i=1;i<=n;i++)
c++,dfs(i,0);
cout << ans<<"\n";
}
int main()
{
fast
cin>>n>>q>>w;
for (int i=0;i<n-1;i++)
{
ll a,b,c;
cin>>a>>b>>c;
len[i]=c;
v[a].pb({b,i});
v[b].pb({a,i});
}
while (q--)
{
ll d,e;
cin>>d>>e;
d=(d+last)%(n-1);
e=(e+last)%w;
len[d]=e;
ans=-1;
c++;
//for (int i=0;i<n-1;i++)\
cout<< len[i]<<" ";\
cout <<"\n";
DFS();
last=ans;
}
return 0;
}
