Untitled

#include <cstdio>
#include <algorithm>
#include <vector>

using namespace std;

const int MAXD = 1010;

int D, m, n;

vector<int> E[MAXD];
vector<int> R[MAXD];
int dokaz[MAXD];

bool bio[MAXD];
bool state[MAXD];
vector<int> topo;

void init( int x ) {
  if( bio[x] ) return;
  bio[x] = true;

  for( vector<int>::iterator it = E[x].begin(); it != E[x].end(); ++it ) init( *it );
  topo.push_back( x );
}

void iskljuci( int x ) {
  if( bio[x] ) return;
  bio[x] = true;

  state[x] = false;
  for( vector<int>::iterator it = R[x].begin(); it != R[x].end(); ++it )
    iskljuci( *it );
}

bool parent( int x ) {
  for( vector<int>::iterator it = R[x].begin(); it != R[x].end(); ++it )
    if( state[*it] ) return true;
  return R[x].empty();
}

int main( void ) {
  scanf( "%d %d %d", &D, &m, &n );

  for( int i = 0; i < m; ++i ) {
    int a, b; scanf( "%d %d", &a, &b ); --a, --b;
    E[a].push_back( b );
    R[b].push_back( a );
  }

  for( int i = 0; i < D; ++i ) init( i );
  reverse( topo.begin(), topo.end() );

  for( int i = 0; i < n; ++i ) {
    scanf( "%d", &dokaz[i] );
    --dokaz[i];
  }

  for( int i = 0; i < D; ++i ) {
    for( int j = 0; j < D; ++j ) state[j] = true;
    for( int j = 0; j < D; ++j ) bio[j] = false;

    iskljuci( i );
    for( vector<int>::iterator it = topo.begin(); it != topo.end(); ++it )
      if( !parent( *it ) ) iskljuci( *it );

    bool ok = true;
    for( int j = 0; j < n && ok; ++j )
      if( !state[ dokaz[j] ] ) ok = false;
    if( !ok ) printf( "%d\n", i+1 );
  }

  return 0;
}