/*
TASK:move
LANG:C++
*/

#include<iostream.h>
 int main()
 {
  int n,m,i,a,b;
  char t=0;
  cin>>n>>m;
  for(i=0;i<m;i++)
   cin>>a>>b;
  for(i=0;i<n;i++){cin>>a; if(a!=i+1)t=1;}
  if(t==0)cout<<"0\n";
   else cout<<"-1"<<endl;
  return 0;
 }