#include <bits/stdc++.h>
#define pb push_back
#define F first
#define S second
#define debug(x) cout << #x << "= " << x << ", "
#define ll long long
#define fast ios::sync_with_stdio(false), cin.tie(0), cout.tie(0)
#define SZ(x) (int) x.size()
#define wall cout << endl;
using namespace std;
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
#define pii pair<int , int>
const int maxn = 1e5 + 10;
int n , q , dp_down[maxn] , w , mx[2][maxn] , par[maxn] , ch[maxn] , val_par[maxn];
vector <pair<pii , int>> edges;
vector <pii> adj[maxn];
vector <int> all[maxn];
multiset <int> fbi;
int Find_ans(int v)
{
int res = 0;
if(SZ(all[v]) >= 1) res += all[v].back();
if(SZ(all[v]) >= 2) res += all[v][SZ(all[v]) - 2];
return res;
}
void dfs(int v)
{
for(auto u : adj[v]) if(u.F != par[v])
{
par[u.F] = v;
val_par[u.F] = u.S;
dfs(u.F);
all[v].pb(dp_down[u.F] + u.S);
}
sort(all[v].begin() , all[v].end());
if(!all[v].empty())
dp_down[v] = all[v].back();
fbi.insert(Find_ans(v));
}
void Find_ch(int v , int child)
{
if(v == 0) return;
int tmp = dp_down[child] + val_par[child];
ch[v] = lower_bound(all[v].begin() , all[v].end() , tmp) - all[v].begin();
tmp = Find_ans(v);
auto it = fbi.find(tmp);
fbi.erase(it);
Find_ch(par[v] , v);
}
void Update(int v , int child)
{
if(v == 0) return;
all[v][ch[v]] = dp_down[child] + val_par[child];
sort(all[v].begin() , all[v].end());
dp_down[v] = all[v].back();
fbi.insert(Find_ans(v));
Update(par[v] , v);
}
int32_t main()
{
fast;
cin >> n >> q >> w;
bool ok = true;
for(int i = 0 ; i < n - 1 ; i++)
{
int v , u , c; cin >> v >> u >> c;
edges.pb({{v , u} , c});
adj[u].pb({v , c}); adj[v].pb({u , c});
if(v != 1 && u != 1) ok = false;
}
if(ok)
{
multiset <int> st;
for(auto u : edges) st.insert(u.S);
int last = 0;
while(q--)
{
int id , val; cin >> id >> val;
id = (id + last) % (n - 1);
val = (val + last) % w;
auto it = st.find(edges[id].S);
st.erase(it);
st.insert(val);
edges[id].S = val;
it = st.end();
it--;
if(SZ(st) == 1) last = *it;
if(SZ(st) >= 2)
{
last = *it;
it--;
last += *it;
}
cout << last << endl;
}
return 0;
}
dfs(1);
int last = 0;
while(q--)
{
int id , val; cin >> id >> val;
id = (id + last) % (n - 1);
val = (val + last) % w;
int v = edges[id].F.F , u = edges[id].F.S;
if(v == par[u]) swap(v , u);
Find_ch(u , v);
val_par[v] = val;
Update(u , v);
auto it = fbi.end();
it--;
int ans = *it;
cout << ans << endl;
last = ans;
}
return 0;
}
