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#include <bits/stdc++.h>
#define f first
#define s second
using namespace std;
using ll = long long;
using ii = pair<int, int>;
vector<ii> G[100001];
unordered_map<int, ll> A[100001], B[100001];
ll dfs(int u, int p) {
sort(begin(G[u]), end(G[u]));
ll ret = 0, sa = 1, tmp = 0, l = -1;
++A[u][0], ++B[u][1e9+7];
for (auto& v : G[u]) {
if (v.s != p) {
ret += dfs(v.s, u);
ll ca = 0, cb = 0;
for (auto& x : A[v.s]) {
if (x.f < v.f) ca += x.s, A[u][v.f] += x.s;
}
for (auto& x : B[v.s]) {
if (x.f > v.f) cb += x.s, B[u][v.f] += x.s;
}
ret += cb * sa, sa += ca;
if (v.f != l) l = v.f, tmp = ca;
else ret -= cb * tmp, tmp += ca;
}
}
return ret + sa - 1;
}
int main() {
int N;
cin >> N;
for (int i = 1, a, b, e; i < N; ++i) {
cin >> a >> b >> e;
G[a].emplace_back(e, b), G[b].emplace_back(e, a);
}
cout << dfs(1, 0) << '\n';
}
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