#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define f first
#define s second
const ll inf = 1e10;
static inline ll diameter(const multiset<ll>& S) {
if (S.size() == 1)
return *S.rbegin();
auto it1 = prev(S.end());
ll a = *it1;
auto it2 = prev(it1);
ll b = *it2;
return a + b;
}
int main() {
ios::sync_with_stdio(false);
cin.tie(nullptr);
ll n, q, wlim;
cin >> n >> q >> wlim;
vector<ll> wts(n - 1);
multiset<ll> S;
for (ll i = 0; i < n - 1; ++i) {
ll a, b, c;
cin >> a >> b >> c;
wts[i] = c;
S.insert(c);
}
ll last = 0;
while (q--) {
ll d, e;
cin >> d >> e;
ll d1 = (d + last) % (n - 1);
ll e1 = (e + last) % wlim;
auto it = S.find(wts[d1]);
S.erase(it);
wts[d1] = e1;
S.insert(e1);
ll ans;
if (n == 2) {
ans = *S.rbegin();
} else {
ans = diameter(S);
}
cout << ans << '\n';
last = ans;
}
}
