#include<bits/stdc++.h>

using namespace std;

const int N=;

int ne[N],num,fi[N],n,k,m,x,y,ans,zz[N],f[N],sum[N],x1[N];

void jb(int x,int y)

{

    ne[++num]=fi[x];

    fi[x]=num;

    zz[num]=y;

}

void dfs(int x)

{

    f[x]=;

    sum[x]++;

    for (int i=fi[x];i;i=ne[i])

     if (!f[zz[i]])dfs(zz[i]);

}

int main()

{

    scanf("%d%d%d",&k,&n,&m);

    for (int i=;i<=k;i++)scanf("%d",&x1[i]);

    while (m--)

     {

         scanf("%d%d",&x,&y);

         jb(x,y);

     }

    for (int i=;i<=k;i++)

     {

         memset(f,,sizeof f);

         dfs(x1[i]);

     }

    for (int i=;i<=n;i++)

     if (sum[i]==k)ans++;

    printf("%d",ans);

    return ;

}