#include<bits/stdc++.h>
#define debug(x) cerr << #x << " " << x << "\n"
#define debugs(x) cerr << #x << " " << x << " "
#pragma GCC optimize("Ofast")
///#define int long long
using namespace std;
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
int range_rng(int l, int r)
{
return uniform_int_distribution<int>(l,r)(rng);
}
struct muchie
{
int a;
int b;
int c;
};
struct ceva
{
int to;
int w;
};
struct cmp
{
bool operator()(ceva a, ceva b) const
{
return a.to<b.to;///efectiv orice
}
};
pair<int,int> mxs[100005];
muchie edge[100005];
set<ceva,cmp> nodes[100005];
multiset<int> rez;
int p[100005];
void mergemax(int parent, int child, int cost)
{
if (mxs[child].first+cost>mxs[parent].first)
{
mxs[parent].second=mxs[parent].first;
mxs[parent].first=mxs[child].first+cost;
}
else if (mxs[child].first+cost>=mxs[parent].second)
{
mxs[parent].second=mxs[child].first+cost;
}
}
void dfs(int node, int parent)
{
mxs[node].first=0;
mxs[node].second=0;
for (auto x : nodes[node])
{
if (x.to!=parent)
{
p[x.to]=node;
dfs(x.to,node);
mergemax(node,x.to,x.w);
}
}
rez.insert(mxs[node].first+mxs[node].second);
}
void update(int node)
{
rez.erase(rez.find(mxs[node].first+mxs[node].second));
mxs[node].first=0;
mxs[node].second=0;
for (auto x : nodes[node])
{
if (x.to!=p[node])
{
mergemax(node,x.to,x.w);
}
}
rez.insert(mxs[node].first+mxs[node].second);
if (p[node]!=0)
update(p[node]);
}
signed main()
{
/*
ifstream fin("arbore.in");
ofstream fout("arbore.out");
*/
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
int n,q,w,i,j,a,b,c,d,e,last,parent,child;
cin >> n >> q >> w;
for (i=1;i<=n-1;i++)
{
cin >> a >> b >> c;
nodes[a].insert({b,c});
nodes[b].insert({a,c});
edge[i]={a,b,c};
}
dfs(1,-1);
last=0;
for (i=1;i<=q;i++)
{
cin >> d >> e;
d=(d+last)%(n-1);
d++;
e=(e+last)%w;
a=edge[d].a;
b=edge[d].b;
if (p[a]==b)
{
parent=b;
child=a;
}
else
{
parent=a;
child=b;
}
nodes[parent].erase({child,edge[d].c});
nodes[child].erase({parent,edge[d].c});
edge[d].c=e;
nodes[parent].insert({child,edge[d].c});
nodes[child].insert({parent,edge[d].c});
update(parent);
cout << (*prev(rez.end())) << "\n";
last=(*prev(rez.end()));
}
return 0;
}
