#include <bits/stdc++.h>
using namespace std;
#ifdef LOCAL
#include "algo/debug.h"
#else
#define debug(...) 42
#endif
template <class T> bool ckmax(T &a, T b) { return a < b ? (a = b, true) : false; }
template <class T> bool ckmin(T &a, T b) { return a > b ? (a = b, true) : false; }
#define int long long
/*
Dung euler tour 2n-1. Khi do duong kinh la max cua bieu thuc:
dep[i] - 2 * dep[j] + dep[k]
i < j < k
Luc nay j la lca cua (i, k)
*/
const int MAXN = 4e5 + 5;
vector<pair<int, int>> g[MAXN];
tuple<int, int, int> e[MAXN];
int euler[MAXN], in[MAXN], out[MAXN], timeDfs = 0;
int dep[MAXN];
void dfs(int u, int p) {
euler[++timeDfs] = u;
in[u] = timeDfs;
for (auto [v, w] : g[u]) {
if (v != p) {
dep[v] = dep[u] + w;
dfs(v, u);
euler[++timeDfs] = u;
}
}
out[u] = timeDfs;
}
struct Node {
int mndep, mxdep, mxsubL, mxsubR, diam;
// mxsubL: dep[i] - 2 * dep[j]
// mxsubR: -2 * dep[j] + dep[k]
Node() {}
Node(int val) {
mndep = mxdep = val;
mxsubL = mxsubR = -val;
diam = 0;
}
Node operator+(const Node &other) const {
Node res;
res.mxdep = max(mxdep, other.mxdep);
res.mndep = min(mndep, other.mndep);
res.mxsubL = max({mxsubL, other.mxsubL, mxdep - 2 * other.mndep});
res.mxsubR = max({mxsubR, other.mxsubR, -2 * mndep + other.mxdep});
res.diam = max({diam, other.diam, mxsubL + other.mxdep, mxdep + other.mxsubR});
return res;
}
void add(int val) {
mxdep += val;
mndep += val;
mxsubL -= val;
mxsubR -= val;
}
};
struct segtree {
Node st[MAXN * 4];
int lazy[MAXN * 4];
int n;
void apply(int id, int val) {
st[id].add(val);
lazy[id] += val;
}
void push(int id) {
if (lazy[id] == 0) return;
apply(id << 1, lazy[id]);
apply(id << 1 | 1, lazy[id]);
lazy[id] = 0;
}
void build(int id, int l, int r) {
lazy[id] = 0;
if (l == r) {
st[id] = Node(dep[euler[l]]);
return;
}
int mid = (l + r) >> 1;
build(id << 1, l, mid);
build(id << 1 | 1, mid + 1, r);
st[id] = st[id << 1] + st[id << 1 | 1];
}
void update(int id, int l, int r, int u, int v, int val) {
if (v < l || r < u) return;
if (u <= l && r <= v) {
apply(id, val);
return;
}
push(id);
int mid = (l + r) >> 1;
update(id << 1, l, mid, u, v, val);
update(id << 1 | 1, mid + 1, r, u, v, val);
st[id] = st[id << 1] + st[id << 1 | 1];
}
Node query(int id, int l, int r, int u, int v) {
if (u <= l && r <= v) return st[id];
push(id);
int mid = (l + r) >> 1;
if (u > mid) return query(id << 1 | 1, mid + 1, r, u, v);
if (v <= mid) return query(id << 1, l, mid, u, v);
return query(id << 1, l, mid, u, v) + query(id << 1 | 1, mid + 1, r, u, v);
}
void build(int N) {
n = N;
build(1, 1, n);
}
void update(int l, int r, int val) {
update(1, 1, n, l, r, val);
}
Node get(int l, int r) {
if (l > r) return Node();
return query(1, 1, n, l, r);
}
} st;
signed main() {
#define NAME "test"
if (fopen(NAME".inp", "r")) {
freopen(NAME".inp", "r", stdin);
freopen(NAME".out", "w", stdout);
}
ios_base::sync_with_stdio(false);
cin.tie(nullptr);
int n, q;
int maxWeight;
cin >> n >> q >> maxWeight;
for (int i = 1; i < n; i++) {
int u, v, w; cin >> u >> v >> w;
g[u].emplace_back(v, w);
g[v].emplace_back(u, w);
e[i] = {u, v, w};
}
dfs(1, 1);
st.build(2 * n - 1);
int last = 0;
while (q--) {
int d, ej; cin >> d >> ej;
d = (d + last) % (n - 1) + 1;
ej = (ej + last) % maxWeight;
auto &[u, v, w] = e[d];
if (dep[u] < dep[v]) swap(u, v);
st.update(in[u], out[u], ej - w);
w = ej;
last = st.st[1].diam;
cout << last << '\n';
}
return 0;
}
