#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;
const int maxn = 1e4 + 5;
int n, a[maxn], p[maxn];
vector <int> adj[maxn];
bool f[maxn][105][105];
vector <int> vt;
bool cmp(int i, int j) {
return a[i] < a[j];
}
void DFS1(int u) {
vt.push_back(u);
for(int v : adj[u]) {
if(v == p[u]) continue;
p[v] = u;
DFS1(v);
}
}
void solve() {
for(int id = int(vt.size() - 1); id >= 0; --id) {
int u = vt[id];
int d = lower_bound(adj[u].begin(), adj[u].end(), u, cmp) - adj[u].begin();
f[u][a[u]][a[u]] = 1;
for(int i = d - 1; i >= 0; --i) {
int v = adj[u][i];
if(v == p[u]) continue;
for(int j = 1; j < a[u]; ++j) {
for(int j1 = j; j1 < a[u]; ++j1) f[u][j][a[u]] |= (f[u][j1 + 1][a[u]] & f[v][j][j1]);
}
}
for(int i = d; i < int(adj[u].size()); ++i) {
int v = adj[u][i];
if(v == p[u]) continue;
for(int j = a[u] + 1; j <= 100; ++j) {
for(int j1 = j; j1 <= 100; ++j1) f[u][a[u]][j1] |= (f[u][a[u]][j - 1] & f[v][j][j1]);
}
}
for(int i = 1; i <= a[u]; ++i) {
for(int j = a[u]; j <= 100; ++j) f[u][i][j] |= (f[u][i][a[u]] & f[u][a[u]][j]);
}
}
}
int main()
{
ios_base::sync_with_stdio(NULL); cin.tie(nullptr);
cin >> n;
for(int i = 1; i <= n; ++i) cin >> a[i];
for(int i = 1; i < n; ++i) {
int u, v;
cin >> u >> v;
adj[u].push_back(v);
adj[v].push_back(u);
}
for(int i = 1; i <= n; ++i) sort(adj[i].begin(), adj[i].end(), cmp);
DFS1(1);
solve();
int res =0 ;
for(int i = 1; i <= 100; ++i) {
for(int j = i; j <= 100; ++j) {
if(f[1][i][j]) ++res;
}
}
cout << res;
return 0;
}
