#include <bits/stdc++.h>
#define REP(i, n) for (int i = 0; (i) < (int)(n); ++ (i))
using namespace std;


int64_t solve(int n, const vector<vector<pair<int, int> > > & g) {
    int64_t ans = 0;
    function<pair<map<int, int>, map<pair<int, int>, int> > (int, int)> go = [&](int x, int parent) {
        int sum_one = 0;
        map<int, int> one;
        map<pair<int, int>, int> two;
        map<pair<int, int>, int> two_lazy;
        map<int, int> two_contains;
        auto add_two = [&](int c, int d, int k) {
            if (c > d) swap(c, d);
            ans += (int64_t)k;
            ans += (int64_t)k * two[make_pair(c, d)];
            ans += (int64_t)k * (one.count(c) ? one[c] : 0);
            ans += (int64_t)k * (one.count(d) ? one[d] : 0);
            two_lazy[make_pair(c, d)] += k;
        };
        auto add_one = [&](int c, int k) {
            ans += (int64_t)k * (sum_one - one[c]);
            ans += (int64_t)k * (two_contains.count(c) ? two_contains[c] : 0);
            one[c] += k;
            sum_one += k;
        };
        for (auto [y, c] : g[x]) if (y != parent) {
            auto [sub_one, sub_two] = go(y, x);
            for (auto [de, k] : sub_two) {
                auto [d, e] = de;
                if (d == c or e == c) {
                    add_two(d, e, k);
                }
            }
            for (auto [d, k] : sub_one) {
                if (d != c) {
                    add_two(c, d, k);
                }
            }
            add_one(c, 1 + (sub_one.count(c) ? sub_one[c] : 0));
            for (auto [de, k] : two_lazy) {
                auto [d, e] = de;
                two[de] += k;
                two_contains[d] += k;
                two_contains[e] += k;
            }
            two_lazy = map<pair<int, int>, int>();
        }
        return make_pair(one, two);
    };
    go(0, -1);
    return ans;
}

int main() {
    int n, k; cin >> n >> k;
    vector<vector<pair<int, int> > > g(n);
    REP (i, n - 1) {
        int u, v, c; cin >> u >> v >> c;
        -- u;
        -- v;
        g[u].emplace_back(v, c);
        g[v].emplace_back(u, c);
    }
    cout << solve(n, g) << endl;
    return 0;
}