#include <iostream>
#include <algorithm>
#include <vector>

using namespace std;

void dfs(vector<vector<int>> &G, int v, vector<bool> &seen, vector<int> &vlist)
{
    seen[v] = true;
    for(auto u:G[v]){
        if (seen[u]) continue;
        dfs(G,u,seen,vlist);
    }
    vlist.push_back(v);
}

vector<int> topological_sort(vector<vector<int>> &G)
{
    int V = G.size();
    vector<bool> seen(V);
    vector<int> res;
    for(int v=0; v<V; v++){
        if (!seen[v]){
            dfs(G,v,seen,res);
        }
    }
    reverse(res.begin(),res.end());
    return res;
}

int main()
{
    int N,M; cin>>N>>M;
    vector<int> A(N);
    for(int i=0; i<N; i++) cin>>A[i];

    vector<vector<int>> G(N);
    for(int i=0; i<M; i++){
        int u,v; cin>>u>>v; u--; v--;
        if (A[u]==A[v]) continue;
        if (A[u] < A[v]) G[u].push_back(v);
        else G[v].push_back(u);
    }

    int K; cin>>K;
    vector<bool> lit(N);
    for(int i=0; i<K; i++){
        int B; cin>>B;
        lit[B-1] = true;
    }

    auto v = topological_sort(G);
    vector<int> ans;
    for(int i=0; i<N; i++){
        if (lit[v[i]]){
            ans.push_back(v[i]);
            for(auto u:G[v[i]]){
                lit[u] = !lit[u];
            }
        }
    }

    cout<<ans.size()<<endl;
    for(auto e:ans){
        cout<<e+1<<endl;
    }
    return 0;
}