#include <bits/stdc++.h>
using namespace std;
const int N = 7e4 + 1;
const int M = 2001;
int n, m;
int a[N];
vector<int> adj[N];
bool dp[N][M];
bool cmp(int u, int v) {
return a[u] < a[v];
}
void calc_dp(int u) {
for (int v : adj[u]) calc_dp(v);
int j = a[u] + 1;
dp[u][a[u]] = true;
sort(adj[u].begin(), adj[u].end(), cmp);
for (int v : adj[u]) {
if (a[v] <= a[u]) continue;
if (dp[v][j]) {
j = max(j, a[v]);
while (j <= 100 && dp[v][j]) {
dp[u][j] = true;
j++;
}
}
}
reverse(adj[u].begin(), adj[u].end());
j = a[u] - 1;
for (int v : adj[u]) {
if (a[v] >= a[u]) continue;
if (dp[v][j]) {
j = min(j, a[v]);
while (j >= 1 && dp[v][j]) {
dp[u][j] = true;
j--;
}
}
}
}
void Solve() {
cin >> n;
for (int i = 1; i <= n; i++) cin >> a[i];
for (int i = 2; i <= n; i++) {
int u, v; cin >> u >> v;
adj[u].push_back(v);
}
calc_dp(1);
int l = 0, r = 0;
for (int i = 1; i <= a[1]; i++) if(dp[1][i]) l++;
for (int i = a[1]; i <= 100; i++) if(dp[1][i]) r++;
cout << l * r;
}
int main() {
ios_base::sync_with_stdio(false);
cin.tie(NULL); cout.tie(NULL);
// freopen("uzastopni.inp", "r", stdin);
//freopen("uzastopni.out", "w", stdout);
Solve();
}
