#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using pll = pair<ll, ll>;
using Edge = pair<ll, pll>;
#define fi first
#define se second
const int maxN = 1e5 + 5;
const ll INF = 1e18;
ll n, q, w;
vector<pll> adj[maxN];
vector<Edge> edges;
ll timer;
ll dist[maxN], tin[maxN], tout[maxN];
vector<ll> Euler(1);
void dfs(ll cur, ll par, ll cdist) {
dist[cur] = cdist;
Euler.push_back(cur);
tin[cur] = (ll)Euler.size() - 1;
for (auto &[nxt, w] : adj[cur]) {
if (nxt == par) continue;
dfs(nxt, cur, cdist+w);
Euler.push_back(cur);
}
tout[cur] = (ll)Euler.size() - 1;
}
struct Segtree {
struct Node {
ll A, B, AB, BA, ABA, lazy;
Node() {}
Node(ll val) {
A = val;
B = -2ll * val;
AB = BA = ABA = -INF;
lazy = 0;
}
};
ll sz;
vector<Node> seg;
Segtree(ll sz) : sz(sz) {
seg.assign((sz << 2) + 1, Node());
}
void updateNode(ll pos, ll val) {
Node &C = seg[pos];
C.A += val;
C.B -= 2ll * val;
C.AB -= val;
C.BA -= val;
C.lazy += val;
}
void checkLazy(ll pos) {
if (seg[pos].lazy != 0) {
ll lc = pos << 1, rc = lc | 1;
updateNode(lc, seg[pos].lazy);
updateNode(rc, seg[pos].lazy);
seg[pos].lazy = 0;
}
}
Node merge(Node L, Node R) {
Node N = Node(0);
N.A = max(L.A, R.A);
N.B = max(L.B, R.B);
N.AB = max({
L.AB,
R.AB,
L.A + R.B
});
N.BA = max({
L.BA,
R.BA,
L.B + R.A
});
N.ABA = max({
L.ABA,
R.ABA,
L.A + R.BA,
L.AB + R.A
});
return N;
}
void build(ll pos, ll l, ll r) {
if (l == r) {
seg[pos] = Node(dist[Euler[l]]);
return;
}
ll m = (l+r) >> 1, lc = pos << 1, rc = lc | 1;
build(lc, l, m);
build(rc, m+1, r);
seg[pos] = merge(seg[lc], seg[rc]);
}
void build() {build(1, 1, sz);}
void update(ll pos, ll l, ll r, ll ul, ll ur, ll val) {
if (l > r || ul > ur || l > ur || ul > r) return;
if (ul <= l && r <= ur) {
updateNode(pos, val);
return;
}
checkLazy(pos);
ll m = (l+r) >> 1, lc = pos << 1, rc = lc | 1;
update(lc, l, m, ul, ur, val);
update(rc, m+1, r, ul, ur, val);
seg[pos] = merge(seg[lc], seg[rc]);
}
void update(ll ul, ll ur, ll val) {update(1, 1, sz, ul, ur, val);}
ll query() {
return max({seg[1].ABA, seg[1].AB, seg[1].BA});
}
};
int main() {
scanf("%lld %lld %lld", &n, &q, &w);
for (ll a, b, c, i = 1; i < n; i++) {
scanf("%lld %lld %lld", &a, &b, &c);
adj[a].push_back({b, c});
adj[b].push_back({a, c});
edges.push_back({c, {a, b}});
}
dfs(1, 0, 0);
ll ES = (ll)Euler.size() - 1;
Segtree S(ES);
S.build();
for (auto &[cw, p] : edges) {
if (tin[p.se] < tin[p.fi]) {swap(p.fi, p.se);}
}
ll last = 0;
for (ll d, e, i = 1; i <= q; i++) {
scanf("%lld %lld", &d, &e);
d = (d + last) % (n - 1);
e = (e + last) % w;
auto &[cw, p] = edges[d];
S.update(tin[p.se], tout[p.se], e - cw);
cw = e;
last = S.query();
printf("%lld\n", last);
}
}
