#include<bits/stdc++.h>
using namespace std;
#define debug(...) 42
#define int long long
using ll = long long;
const int maxn = 1e4 + 10;
const int maxk = 1e2 + 5;
vector<pair<int,int>> s[maxn];
vector<int> ad[maxn];
int val[maxn];
vector<int> q[maxk];
bitset<maxk> f[maxn][maxk];
void dfs(int u){
for (auto v : ad[u]) dfs(v);
for (int i = 0; i < maxk; i++) q[i].clear();
for (auto v : ad[u]){
for (auto [a, b] : s[v]){
q[a].push_back(b);
}
}
for (int l = maxk - 1; l >= 1; l--){
if (l == val[u]){
f[u][l] |= f[u][l + 1];
f[u][l][l] = 1;
}
else{
for (auto h : q[l]){
if (h < val[u] || l > val[u]) {
f[u][l] |= f[u][h + 1];
f[u][l][h] = 1;
}
}
}
for (int h = maxk - 1; h >= l; h--)
if (f[u][l][h] && val[u] >= l && val[u] <= h) {
s[u].emplace_back(l, h);
}
}
}
void solve(){
int n;
cin >> n;
for (int i = 1; i <= n; i++) cin >> val[i];
for (int i = 0; i < n - 1; i++){
int u, v;
cin >> u >> v;
ad[u].push_back(v);
}
dfs(1);
cout << s[1].size();
}
int32_t main() {
ios_base::sync_with_stdio(false);
cin.tie(0);
int tt = 1;
// cin >> tt;
while (tt--){
solve();
}
return 0;
}
