#include <bits/stdc++.h>
#define rep(i,n) for (int i=0; i < (n); i++)
using namespace std;
using ll = long long;

int main(){
    ios::sync_with_stdio(false);
    int N,M; cin>>N>>M;
    vector<int> A(N+1,0);
    vector<int> light(N+1,0);
    rep(i,N){
        int a;
        cin>>a; A[i+1] = -a;
    }
    vector<vector<int>> load(N+1,vector<int>());
    rep(i,M){
        int u,v; cin>>u>>v;
        load[u].push_back(v);
        load[v].push_back(u);
    }

    priority_queue<pair<int,int>> que; //強さ・番号
    int K; cin>>K;
    rep(i,K){
        int B; cin>>B;
        light[B]=1;
        que.push(make_pair(A[B],B));
    }

    vector<int> ans;
    while(que.size()){
        auto x = que.top(); que.pop();
        int a = x.first, b=x.second;
        if(light[b]==0) continue;
        light[b]=0;
        // cerr << a << " " << b  <<endl;
        ans.push_back(b);
        for(int s:load[b]){
            if(A[s]<a){
                light[s] = (light[s]+1)%2;
            }
            if(light[s]){
                que.push(make_pair(A[s],s));
            }
        }
    }

    cout << ans.size() << endl;
    for(int x:ans){
        cout << x << endl;
    }

}