#include <iostream>
#include<vector>
using namespace std;

int k,n,m;

vector<int> v[1001];
int at[101];
bool b[1001];
int sum[1001];

void dfs(int x)
{
	b[x]=true;
	int next;
	for (int i=0,len=v[x].size();i<len;++i)
	{
		next=v[x][i];
		if (b[next])
			continue;
		dfs(next);		
	}
}

int main()
{
	int i,j;
	cin>>k>>n>>m;
	
	for (i=1;i<=k;i++)
		scanf("%d",at+i);
	
	while (m--)
	{
		scanf("%d%d",&i,&j);
		v[i].push_back(j);
	}
	
	memset(sum,0,sizeof(sum));
	memset(b,false,sizeof(b));
	for (i=1;i<=k;++i)
	{
		dfs(at[i]);
		for (j=1;j<=n;++j)
			sum[j]+=b[j],b[j]=false;
	}
	
	int ans=0;
	for (i=1;i<=n;++i)
	{
		if (sum[i]==k)
			ans++;
	}
	
	printf("%d\n",ans);
	
	
	
	
	return 0;
}