#include <iostream>
#include <algorithm>
#include <cstring>
#include <vector>
#include <queue>

using namespace std;

const int N = 1e3 + 10;

int k, n, m;
bool g[N][N];
int cnt[N];
int cows[N];
bool st[N];

bool bfs(int u)
{
	queue<int> q;
	q.push(u);
	st[u] = true;
	cnt[u]++;
	
	while(q.size())
	{
		int t = q.front();
		q.pop();
		
		st[t] = true;
		
		for(int i = 1; i <= n; i++)
			if(!st[i] && i != t && g[t][i])
			{
			    q.push(i);
			    cnt[i]++;
			}
				
	}
}

int main()
{
	scanf("%d%d%d", &k, &n, &m);
	
	for(int i = 1; i <= k; i++) scanf("%d", &cows[i]);
	
	for(int i = 1; i <= n; i++) g[i][i] = true;
	
	int a, b;
	while(m--)
	{
		scanf("%d%d", &a, &b);
		g[a][b] = true;
	}
	
    for(int i = 1; i <= k; i++)
    {
        bfs(cows[i]);
        memset(st, 0, sizeof st);
    }
        
    
    int res = 0;
    for(int i = 1; i <= n; i++)
        if(cnt[i] == k)
            res++;
	
	printf("%d\n", res);
	
	return 0;
}