#include <iostream>
#include<bits/stdc++.h>

using namespace std;
const int inf = 1e5 ;

int main()
{
    int n , m , k ;
    cin >> n >> m >> k ;

    vector<int> v(k) ;
    for(int i = 0 ; i < k ; i++)
        cin >> v[i] ;

    vector<vector<int> > adj(n + 1) ;
    for(int i = 1 ; i <= m ; i++)
    {
        int u , v ;
        cin >> u >> v ;

        adj[u].push_back(v) ;
        adj[v].push_back(u) ;
    }

    vector<vector<int> > d(n + 1 , vector<int>(n + 1 , inf)) ;
    vector<vector<int> > cnt(n + 1 , vector<int>(n + 1 , 0)) ;
    for(int i = 1 ; i <= n ; i ++)
    {
        d[i][i] = 0 ;
        cnt[i][0] = 1 ;
    }


    for(int i = 1 ; i <= n ; i++)
    {
        queue<int> q ;
        q.push(i) ;
        while(!q.empty())
        {
            int v = q.front() ;
            q.pop() ;

            for(int to : adj[v])
            {
                if(d[i][to] != inf) continue ;
                d[i][to] = d[i][v] + 1 ;
                cnt[i][d[i][v] + 1 ]++ ;
                q.push(to) ;
            }
        }
    }

    vector<int> ans ;
    for(int i = 1 ; i <= n ; i++)
    {

        bool good = true ;
        for(int j = 1 ; j < k ; j++)
            if(d[i][v[j] ] < d[i][v[j - 1] ] || d[i][v[j] ] > d[i][v[j - 1] ] + 1)
                good = false ;
        if(good)
            ans.push_back(i) ;
    }

    cout << ans.size() << "\n" ;
    for(int v : ans)
        cout << v << " " ;


    return 0;
}