#include <bits/stdc++.h>
using namespace std;

const int N = 2005;
int n, w[N], x, y, v, head[N], dep[N], mp[N][N], ans[N], res, tot;
bool vis[N], flag;
vector<int> g[N];

struct edge {int to, nxt;} e[N << 1];

void add_edge(int u, int v) {e[++tot] = {v, head[u]}, head[u] = tot;}

inline bool check(int i, int j)
{
	return (dep[i] > dep[j] && w[i] <= w[j]);
}

void dfs1(int u, int fa)
{
	dep[u] = dep[fa] + 1;
	for(int i = head[u]; i; i = e[i].nxt)
		if(e[i].to != fa) dfs1(e[i].to, u);
	return;
}

void dfs2(int u, int t)
{
	if(flag) return;
	if(u == v)
	{
		flag = 1;
		for(int i = 1; i <= t; i++)
		for(int j = i + 1; j <= t; j++)
			if(check(ans[i], ans[j]) || check(ans[j], ans[i])) return;
		return (void) (res++);
	}
	for(int i = head[u]; i; i = e[i].nxt)
	{
		if(!vis[e[i].to])
		{
			vis[e[i].to] = 1, ans[t + 1] = e[i].to;
			dfs2(e[i].to, t + 1);
			vis[e[i].to] = 0;	
		}	
	}
	return;
}

int main()
{
	freopen("touch.in", "r", stdin);
	freopen("touch.out", "w", stdout);
	cin >> n;
	for(int i = 1; i <= n; i++) cin >> w[i];
	for(int i = 1; i < n; i++)
	{
		cin >> x >> y;
		add_edge(x, y);
		add_edge(y, x);
	}
	dfs1(1, 0);
	for(int i = 1; i <= n; i++)
	for(int j = i + 1; j <= n; j++)
		if(!check(i, j)) g[i].push_back(j);
	for(int i = 1; i <= n; i++)
	for(auto j : g[i])
	{
		if(i == j) continue;
		memset(vis, 0, sizeof vis);
		v = j, ans[1] = i, flag = 0, vis[i] = 1;
		dfs2(i, 1);
	}
	cout << res;
	return 0;
}