#include<iostream>
using namespace std;
int main()
{
	int N;
	cin>>N;
	int *ar = new int[N];
	for(int i=0;i<N;i++)
		cin>>ar[i];
	int **a = new int* [N];
	for(int i=0;i<N;i++){
		a[i]=new int [N];
		for(int j=0;j<N;j++){
			a[i][j]=-1;
	}
	}
	int u,v;
	for(int i=0;i<N-1;i++){
		cin>>u>>v;
		a[u][v]=ar[v];
	}
	int k;int count=0;
	int j,flg;
	for(int i=0;i<N;i++){
	    k=ar[i];flg=1;
		for(j=0;j<N-1 && flg;j++)
		{
		    if(!(a[i][j] == -1 || a[i][j] == k))
		        flg=0;
	
		}
		if(flg)
			count++;
	}
	cout<<count<<endl;
	for(int i=0;i<N;i++)
		delete[] a[i];
	delete[] ar;
	return 0;
}