#include <bits/stdc++.h>
using namespace std;
const int N = 200000 + 5;
const long long INF = 1000000000000000005LL;
struct Edge {
int u, v;
long long w;
};
struct Node {
long long du, dv, duw, dwv, duwv;
Node() {
du = INF;
dv = -INF;
duw = -INF;
dwv = -INF;
duwv = 0;
}
};
int n, q, m;
long long W, res;
vector<pair<int,int>> adj[N];
Edge edge[N];
int in[N], out[N], ver[N], h[N];
long long d[N];
Node st[4 * N];
long long lz[4 * N];
void euler(int u, int p) {
in[u] = ++m;
out[u] = m;
ver[m] = u;
for (auto it : adj[u]) {
int v = it.first;
int w = it.second;
if (v == p) continue;
h[v] = h[u] + 1;
d[v] = d[u] + w;
euler(v, u);
}
if (p != 0) {
out[p] = ++m;
ver[m] = p;
}
}
long long minimize(long long a, long long b) {
return a < b ? a : b;
}
long long maximize(long long a, long long b) {
return a > b ? a : b;
}
Node mergeNode(const Node &A, const Node &B) {
Node res;
res.du = minimize(A.du, B.du);
res.dv = maximize(A.dv, B.dv);
res.duw = maximize(A.duw, B.duw);
res.duw = maximize(res.duw, A.dv - 2 * B.du);
res.dwv = maximize(A.dwv, B.dwv);
res.dwv = maximize(res.dwv, B.dv - 2 * A.du);
res.duwv = maximize(A.duwv, B.duwv);
res.duwv = maximize(res.duwv, A.duw + B.dv);
res.duwv = maximize(res.duwv, A.dv + B.dwv);
return res;
}
void pushDown(int id) {
long long v = lz[id];
if (v == 0) return;
for (int t = 0; t < 2; t++) {
int c = id * 2 + t;
st[c].du += v;
st[c].dv += v;
st[c].duw -= v;
st[c].dwv -= v;
lz[c] += v;
}
lz[id] = 0;
}
void build(int id, int l, int r) {
if (l == r) {
st[id].du = d[ver[l]];
st[id].dv = d[ver[l]];
st[id].duw = -d[ver[l]];
st[id].dwv = -d[ver[l]];
st[id].duwv = 0;
return;
}
int mid = (l + r) >> 1;
build(id * 2, l, mid);
build(id * 2 + 1, mid + 1, r);
st[id] = mergeNode(st[id * 2], st[id * 2 + 1]);
}
void update(int id, int l, int r, int u, int v, long long x) {
if (l > v || r < u) return;
if (u <= l && r <= v) {
st[id].du += x;
st[id].dv += x;
st[id].duw -= x;
st[id].dwv -= x;
lz[id] += x;
return;
}
pushDown(id);
int mid = (l + r) >> 1;
update(id * 2, l, mid, u, v, x);
update(id * 2 + 1, mid + 1, r, u, v, x);
st[id] = mergeNode(st[id * 2], st[id * 2 + 1]);
}
void solve() {
cin >> n >> q >> W;
for (int i = 1; i < n; i++) {
int u, v, w;
cin >> u >> v >> w;
adj[u].push_back({v, w});
adj[v].push_back({u, w});
edge[i] = {u, v, w};
}
euler(1, 0);
build(1, 1, m);
while (q--) {
int d_id;
long long e;
cin >> d_id >> e;
d_id = (d_id + res) % (n - 1) + 1;
e = (e + res) % W;
int u = edge[d_id].u;
int v = edge[d_id].v;
int w = edge[d_id].w;
if (h[u] > h[v]) swap(u, v);
update(1, 1, m, in[v], out[v], e - w);
res = st[1].duwv;
cout << res << '\n';
edge[d_id].w = e;
}
}
int main() {
ios::sync_with_stdio(false);
cin.tie(nullptr);
solve();
return 0;
}
