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

const int N=3010;

int n,idx,ans;
int dep[N],head[N],nxt[N],ver[N];

bool mk[N];

long long w[N],maxx[N];

struct node{
	int hao,zhi;
}a[N],shi[N];

inline int read(){
	int t=0,f=1;
	register char c=getchar();
	while (c<48||c>57) f=(c=='-')?(-1):(f),c=getchar();
	while (c>=48&&c<=57)t=(t<<1)+(t<<3)+(c^48),c=getchar();
	return f*t;
}

inline long long readl(){
	long long t=0,f=1;
	register char c=getchar();
	while (c<48||c>57) f=(c=='-')?(-1):(f),c=getchar();
	while (c>=48&&c<=57)t=(t<<1)+(t<<3)+(c^48),c=getchar();
	return f*t;
}

bool cmp(node x,node y){
	return x.zhi>y.zhi;
}

void add(int u,int v){
	nxt[++idx]=head[u];
	head[u]=idx;
	ver[idx]=v;
}

void dfsdep(int d,int s){
	dep[d]=s;
	for(int i=head[d];i;i=nxt[i]){
		int dao=ver[i];
		if(dep[dao]) continue;
		dfsdep(dao,s+1);
	}
}

void dfs(int d,int ed,int ci){
	a[ci].hao=d,a[ci].zhi=w[d];
	if(d==ed){
		bool flag=false;
		for(int i=1;i<=ci;i++) shi[i]=a[i];
		sort(shi+1,shi+1+ci,cmp);
		for(int i=2;i<=ci;i++){
//			cout<<a[i].hao<<" ";
			if(dep[a[i].hao]<dep[a[i-1].hao]){
//				cout<<a[i].hao<<endl;
				flag=true;
				break;
			}
		}
//		cout<<endl;
		if(!flag) ans++;
		return;
	}
	for(int i=head[d];i;i=nxt[i]){
		int dao=ver[i];
		if(mk[dao]) continue;
//		cout<<dao<<endl;
		mk[dao]=1;
		dfs(dao,ed,ci+1);
	}
}

int main(){
	freopen("touch.in","r",stdin);
	freopen("touch.out","w",stdout);
	n=read();
	for(int i=1;i<=n;i++) w[i]=readl();
	for(int i=1;i<n;i++){
		int x=read(),y=read();
		add(x,y);
		add(y,x);
	}
	dfsdep(1,1);
	for(int i=1;i<=n;i++){
		for(int j=i+1;j<=n;j++){
			memset(maxx,0,sizeof(maxx));
			memset(mk,0,sizeof(mk));
			mk[i]=1;
			dfs(i,j,1);
		}
	}
	cout<<ans<<'\n';
	return 0;
}