#include <bits/stdc++.h>
// mrrrow meeow :3
// go play vivid/stasis now! it's free on steam
#define fo(i, a, b) for (auto i = (a); i < (b); i++)
#define of(i, a, b) for (auto i = (b); i-- > (a);)
#define f first
#define s second
#define pb push_back
#define pob pop_back
#define lb lower_bound
#define ub upper_bound
#define be(a) a.begin(), a.end()
using namespace std;
int ____init = [] {
ios::sync_with_stdio(false);
cin.tie(NULL);
cout.tie(NULL);
return 0;
}();
struct Node {
long long sum00, sum10, sum01, sum11;
Node() : sum00(0), sum10(0), sum01(0), sum11(0) {}
Node(long long v) : sum00(max(v, 0ll)), sum10(max(v, 0ll)), sum01(max(v, 0ll)), sum11(v) {}
Node combine(const Node &r) const {
const Node &l = *this;
Node res;
res.sum00 = max(max(l.sum00, r.sum00), l.sum01 + r.sum10);
res.sum10 = max(l.sum10, l.sum11 + r.sum10);
res.sum01 = max(l.sum01 + r.sum11, r.sum01);
res.sum11 = l.sum11 + r.sum11;
return res;
}
};
const int N = 1 << 18;
Node st[N * 2];
int l = 0;
void st_set(int i, long long v) {
i += N;
st[i] = Node(v);
for (i /= 2; i > 0; i /= 2) st[i] = st[i * 2].combine(st[i * 2 + 1]);
}
vector<pair<int, pair<int, long long>>> adj[100000];
pair<int, int> eedges[99999];
void dfs(int i, int p = -1) {
for (auto [j, c] : adj[i]) {
if (j == p) continue;
eedges[c.f].f = l;
st[N + l++] = Node(c.s);
dfs(j, i);
eedges[c.f].s = l;
st[N + l++] = Node(-c.s);
}
}
int main() {
int n, q;
long long w;
cin >> n >> q >> w;
fo(i, 0, n - 1) {
int a, b;
long long c;
cin >> a >> b >> c;
a--, b--;
adj[a].pb({b, {i, c}});
adj[b].pb({a, {i, c}});
}
dfs(0);
of(i, 1, N) st[i] = st[i * 2].combine(st[i * 2 + 1]);
long long last = 0;
while (q--) {
long long d, e;
cin >> d >> e;
d = (d + last) % (n - 1);
e = (e + last) % w;
st_set(eedges[d].f, e);
st_set(eedges[d].s, -e);
cout << st[1].sum00 << endl;
last = st[1].sum00;
}
}
