#include <iostream>
#include <vector>
#include <cmath>
#include <map>
#include <set>
#include <iomanip>
#include <queue>
#include <algorithm>
#include <numeric>
#include <deque>
#include <complex>
#include <cassert>

using namespace std;

template<typename T> using pq = priority_queue<T, vector<T>, greater<T>>;
 
int main(){
 
    long long N, M, A, B, C, start, K;
    long long from, alt, d;
    cin >> N >> M;
    pq<pair<long long, long long>> que;
    vector<long long> num(N), ans;
    deque<bool> color(N);
    for (int i=0; i<N; i++) cin >> num[i];
    vector<vector<long long>> E(N);
 
    for (int i=0; i < M; i++){
        cin >> A >> B;
        A--; B--;
        E[A].push_back(B);
        E[B].push_back(A);
    }

    cin >> K;
    for (int i=0; i<K; i++){
        cin >> B; B--;
        color[B] = 1;
        que.push({num[B], B});
    }
 
    while(!que.empty()){
        tie(d, from) = que.top();
        que.pop();
        if (color[from] == 0) continue;
        color[from] = 0;
        ans.push_back(from+1);
        for (auto to : E[from]){
            if (num[to] > num[from]){
                color[to] ^= 1;
                if (color[to] == 1){
                    que.push({num[to], to});
                }
            }
        }
    }

    cout << ans.size() << endl;
    for (auto x : ans) cout << x << endl;
 
    return 0;
}