#include <bits/stdc++.h> using namespace std; vector<vector<int>> child; vector<int> joke; vector<bitset<101>> lans, rans; void dfs(int x) { vector<int> lo, hi; for (int y : child[x]) { dfs(y); if (joke[y] < joke[x]) lo.push_back(y); if (joke[y] > joke[x]) hi.push_back(y); } // Base case: interval containing only joke[x] lans[x][joke[x]] = 1; rans[x][joke[x] + 1] = 1; // Extend to smaller joke types sort(lo.begin(), lo.end(), [&](int a, int b) { return joke[a] > joke[b]; }); for (int y : lo) { if ((lans[x] & rans[y]).any()) { lans[x] |= lans[y]; } } // Extend to larger joke types sort(hi.begin(), hi.end(), [&](int a, int b) { return joke[a] < joke[b]; }); for (int y : hi) { if ((rans[x] & lans[y]).any()) { rans[x] |= rans[y]; } } } int main() { ios::sync_with_stdio(false); cin.tie(nullptr); int N; cin >> N; joke.resize(N); for (int i = 0; i < N; i++) { cin >> joke[i]; --joke[i]; // make joke types 0-based } child.assign(N, {}); for (int i = 0; i < N - 1; i++) { int a, b; cin >> a >> b; --a; --b; child[a].push_back(b); } lans.assign(N, bitset<101>()); rans.assign(N, bitset<101>()); dfs(0); long long ans = 1LL * lans[0].count() * rans[0].count(); cout << ans << "\n"; return 0; }