#include <bits/stdc++.h>
using namespace std;
const int N = 200000 + 5;
const int MAX = 1000000;
const int MOD = 1000000007;
const long long oo = 1000000000000000005LL;
int n, q, m, TIME;
long long W, res;
long long lz[4 * N], d[N];
int in[N], out[N], ver[N], h[N];
vector<pair<int,int>> e[N];
struct ed {
int u, v;
long long w;
} edge[N];
void euler(int u, int p) {
in[u] = ++m;
out[u] = m;
ver[m] = u;
for (auto it : e[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;
}
}
struct node {
long long du, dv, duw, dwv, duwv;
node() {
du = oo;
dv = -oo;
duw = -oo;
dwv = -oo;
duwv = 0;
}
} st[4 * N];
void down(int id) {
st[2 * id].du += lz[id];
st[2 * id].dv += lz[id];
st[2 * id].duw -= lz[id];
st[2 * id].dwv -= lz[id];
lz[2 * id] += lz[id];
st[2 * id + 1].du += lz[id];
st[2 * id + 1].dv += lz[id];
st[2 * id + 1].duw -= lz[id];
st[2 * id + 1].dwv -= lz[id];
lz[2 * id + 1] += lz[id];
lz[id] = 0;
}
long long minimize(const long long &A, const long long &B) {
if (A < B) return A;
return B;
}
long long maximize(const long long &A, const long long &B) {
if (A > B) return A;
return B;
}
node Merge(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 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]];
return;
}
int mid = (l + r) / 2;
build(2 * id, l, mid);
build(2 * id + 1, mid + 1, r);
st[id] = Merge(st[2 * id], st[2 * id + 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;
}
down(id);
int mid = (l + r) / 2;
update(2 * id, l, mid, u, v, x);
update(2 * id + 1, mid + 1, r, u, v, x);
st[id] = Merge(st[2 * id], st[2 * id + 1]);
}
void solve() {
cin >> n >> q >> W;
for (int i = 1; i <= n - 1; i++) {
int u, v, w;
cin >> u >> v >> w;
e[u].push_back({v, w});
e[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_new;
cin >> d_id >> e_new;
d_id = (d_id + res) % (n - 1) + 1;
e_new = (e_new + res) % W;
int u = edge[d_id].u;
int v = edge[d_id].v;
long long w = edge[d_id].w;
if (h[u] > h[v]) swap(u, v);
update(1, 1, m, in[v], out[v], e_new - w);
res = st[1].duwv;
cout << res << "\n";
edge[d_id].w = e_new;
}
}
int main() {
ios_base::sync_with_stdio(false);
cin.tie(nullptr);
int t = 1;
while (t--) {
solve();
}
return 0;
}
