/*
TASK: TRIP
LANG: C++
*/
#include<iostream>
using namespace std;
int s[100][100],v[1000],n,m,k,br,mbr;
void sth(int x=1)
{
 int i;
 v[x]=1;
 for(i=1;i<=n;i++)
 if(s[x][i]&&!v[i])
 {
  br++;
  if(mbr<br)mbr=br;
  sth(i);
  br--;
 }
}
int main()
{
 int i,a,b;
 cin>>n>>m>>k;
 for(i=0;i<m;i++){cin>>a>>b;s[a][b]=s[b][a]=1;}
 for(i=0;i<k;i++){cin>>a;v[a]=1;}
 if(!v[1])br++;
 sth(1);
 cout<<mbr<<endl;
 return 0;
}
