#include <bits/stdc++.h>
#define int long long
using namespace std;
struct node
{
node *lc, *rc;
int l, r;
int mx, lazy;
node(int l, int r) : lc(0), rc(0), l(l), r(r), mx(0), lazy(0) {}
};
void push(node *i)
{
if (!i->lazy)
return;
int mid=(i->l+i->r)/2;
if (!i->lc)
i->lc=new node(i->l, mid);
if (!i->rc)
i->rc=new node(mid+1, i->r);
i->lc->mx+=i->lazy;
i->lc->lazy+=i->lazy;
i->rc->mx+=i->lazy;
i->rc->lazy+=i->lazy;
i->lazy=0;
}
void update(node *i, int ql, int qr, int x)
{
//cout << "update " << (i->l) << ' ' << (i->r) << ' ' << ql << ' ' << qr << ' ' << x << '\n';
if (ql<=i->l && i->r<=qr)
{
i->mx+=x;
i->lazy+=x;
return;
}
push(i);
int mid=(i->l+i->r)/2;
if (i->l<=qr && ql<=mid)
{
if (!i->lc)
i->lc=new node(i->l, mid);
update(i->lc, ql, qr, x);
}
if (mid<qr && ql<=i->r)
{
if (!i->rc)
i->rc=new node(mid+1, i->r);
update(i->rc, ql, qr, x);
}
i->mx=max(i->lc?i->lc->mx:0, i->rc?i->rc->mx:0);
}
vector<pair<pair<int, int>, pair<int, int> > > edge[100005];
vector<pair<int, int> > adj[100005];
multiset<int> s[100005], ss;
vector<node*> seg[100005];
int weight[100005];
void dfs1(unordered_map<int, int> &mp, vector<int> &sz, int u, int p)
{
for (int i=0; i<adj[u].size(); i++)
{
int v=adj[u][i].first;
if (v==p || !mp[v])
continue;
dfs1(mp, sz, v, u);
sz[mp[u]]+=sz[mp[v]];
}
}
int dfs2(unordered_map<int, int> &mp, vector<int> &sz, int u, int p, int n)
{
for (int i=0; i<adj[u].size(); i++)
{
int v=adj[u][i].first;
if (v==p || !mp[v])
continue;
if (sz[mp[v]]*2>n)
return dfs2(mp, sz, v, u, n);
}
return u;
}
void dfs3(unordered_map<int, int> &mp, vector<int> &tin, vector<int> &tout, int u, int p, int &t)
{
tin[mp[u]]=++t;
for (int i=0; i<adj[u].size(); i++)
{
int v=adj[u][i].first;
if (v==p || !mp[v])
continue;
dfs3(mp, tin, tout, v, u, t);
}
tout[mp[u]]=t;
}
void dfs4(unordered_map<int, int> &mp, vector<int> &tmp, vector<int> &tin, vector<int> &tout, int u, int p, int centroid)
{
tmp.push_back(u);
for (int i=0; i<adj[u].size(); i++)
{
int v=adj[u][i].first, w=adj[u][i].second;
if (v==p || !mp[v])
continue;
edge[w].push_back({{centroid, seg[centroid].size()}, {tin[mp[v]], tout[mp[v]]}});
dfs4(mp, tmp, tin, tout, v, u, centroid);
}
}
void recur(vector<int> &vec)
{
if (vec.size()==1)
return;
/*cout << "recur ";
for (int u:vec)
cout << u << ' ';
cout << '\n';*/
vector<int> sz(vec.size()+1, 1), tin(vec.size()+1), tout(vec.size()+1);
unordered_map<int, int> mp;
for (int i=0; i<vec.size(); i++)
mp[vec[i]]=i+1;
dfs1(mp, sz, vec[0], 0);
int centroid=dfs2(mp, sz, vec[0], 0, vec.size()), t=0;
dfs3(mp, tin, tout, centroid, 0, t);
for (int i=0; i<adj[centroid].size(); i++)
{
int v=adj[centroid][i].first, w=adj[centroid][i].second;
if (!mp[v])
continue;
edge[w].push_back({{centroid, seg[centroid].size()}, {tin[mp[v]], tout[mp[v]]}});
//cout << "edge " << w << " push " << centroid << ' ' << seg[centroid].size() << ' ' << tin[mp[v]] << ' ' << tout[mp[v]] << '\n';
vector<int> tmp;
dfs4(mp, tmp, tin, tout, v, centroid, centroid);
recur(tmp);
seg[centroid].push_back(new node(tin[mp[v]], tout[mp[v]]));
//cout << "seg " << centroid << ' ' << seg[centroid].size()-1 << " has range " << tin[mp[v]] << ' ' << tout[mp[v]] << '\n';
s[centroid].insert(0);
}
ss.insert(0);
/*cout << "done recur ";
for (int u:vec)
cout << u << ' ';
cout << '\n';*/
}
void update(int ind, int x)
{
//cout << "update " << ind << ' ' << x << '\n';
for (int i=0; i<edge[ind].size(); i++)
{
int centroid=edge[ind][i].first.first, num=edge[ind][i].first.second, l=edge[ind][i].second.first, r=edge[ind][i].second.second;
//cout << "ss erase " << (s[centroid].size()==1?*s[centroid].begin():*s[centroid].begin()+*next(s[centroid].begin())) << '\n';
ss.erase(ss.find(s[centroid].size()==1?*s[centroid].begin():*s[centroid].begin()+*next(s[centroid].begin())));
//cout << "s erase " << (*s[centroid].find(-seg[centroid][num]->mx)) << '\n';
s[centroid].erase(s[centroid].find(-seg[centroid][num]->mx));
//cout << "here\n";
update(seg[centroid][num], l, r, x);
s[centroid].insert(-seg[centroid][num]->mx);
//cout << "s insert " << (-seg[centroid][num]->mx) << '\n';
ss.insert(s[centroid].size()==1?*s[centroid].begin():*s[centroid].begin()+*next(s[centroid].begin()));
//cout << "ss insert " << (s[centroid].size()==1?*s[centroid].begin():*s[centroid].begin()+*next(s[centroid].begin())) << '\n';
}
}
signed main()
{
ios::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
int n, q, r, ans=0;
cin >> n >> q >> r;
for (int i=0; i<n-1; i++)
{
int u, v;
cin >> u >> v >> weight[i];
adj[u].push_back({v, i});
adj[v].push_back({u, i});
}
vector<int> tmp;
for (int i=1; i<=n; i++)
tmp.push_back(i);
recur(tmp);
for (int i=0; i<n-1; i++)
update(i, weight[i]);
for (int i=1; i<=q; i++)
{
int ind, w;
cin >> ind >> w;
ind=(ind+ans)%(n-1);
w=(w+ans)%r;
update(ind, w-weight[ind]);
weight[ind]=w;
cout << -*ss.begin() << '\n';
ans=-*ss.begin();
}
}
