Untitled

#include <bits/stdc++.h>

using namespace std;

const int MAX_N = 100005;

int n, k;
vector<int> adj[MAX_N];
int a[MAX_N];
int c[MAX_N];
vector<vector<int> > hold;
vector<int> cur;

void backtrack(int i, int l) {
    if (i == n) {
        hold.push_back(cur);
        return;
    }

    for (int x = l + 1; x <= k; x++) {
        cur.push_back(x);
        backtrack(i + 1, x);
        cur.pop_back();
    }
}

int main() {
    ios::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);

    freopen("SCORING.inp", "r", stdin);
    freopen("SCORING.out", "w", stdout);

    cin >> n >> k;

    for (int i = 1; i <= n - 1; i++) {
        int u, v;
        cin >> u >> v;

        adj[u].push_back(v);
        adj[v].push_back(u);
    }

    for (int u = 1; u <= n; u++) {
        cin >> a[u];
    }

    backtrack(0, 0);

    int answer = 0;
    for (auto x : hold) {
        for (int i = 1; i <= n; i++) {
            c[i] = x[i - 1];
        }

        do {
            bool check = true;
            for (int u = 1; u <= n; u++) {
                for (auto v : adj[u]) {
                    if (a[u] > a[v]) {
                        check &= (c[u] > c[v]);
                    }
                }
            }

            answer += check;
        } while (next_permutation(c + 1, c + n + 1));
    }

    cout << answer << '\n';

    return 0;
}