#pragma GCC optimize ("Ofast")
// #pragma GCC target ("avx2")
#include <bits/stdc++.h>
#define X first
#define Y second
#define ll long long
#define MP make_pair
using namespace std;
const int N = 10001, M = 100;
const ll mod = 1e9 + 7;
int n, cl[N];
vector<int> g[N], q[N];
vector< pair<int, int> > ans[N];
bitset<M> dp[N][M];
void dfs(int v) {
for(int to: g[v])
dfs(to);
for(int i = M - 1;i >= 0;i--)
q[i].clear();
for(int to: g[v]) {
for(pair<int, int> &nx: ans[to])
q[nx.X].push_back(nx.Y);
}
q[cl[v]].push_back(cl[v]);
for(int i = M - 1;i >= 0;i--) {
for(int j: q[i]) {
dp[v][i][j] = 1;
if(j + 1 < M)
dp[v][i] |= dp[v][j + 1];
}
if(i > cl[v]) continue;
for(int j = cl[v];j < M;j++) {
if(dp[v][i][j]) ans[v].push_back(MP(i, j));
}
}
}
int main() {
ios::sync_with_stdio(0);
cin.tie(0), cout.tie(0);
cin >> n;
for(int i = 1;i <= n;i++)
cin >> cl[i], cl[i]--;
for(int i = 1, x, y;i < n;i++) {
cin >> x >> y;
g[x].push_back(y);
}
dfs(1);
cout << ans[1].size();
return 0;
}
