#include <algorithm>
#include <bitset>
#include <cassert>
#include <cmath>
#include <cstdio>
#include <fstream>
#include <functional>
#include <iomanip>
#include <iostream>
#include <iterator>
#include <map>
#include <numeric>
#include <queue>
#include <set>
#include <sstream>
#include <unordered_set>
using namespace std;
#if __has_include(<atcoder/all>)
#include <atcoder/all>
using namespace atcoder;
#endif
#define GET_MACRO(_1, _2, _3, NAME, ...) NAME
#define _rep(i, n) _rep2(i, 0, n)
#define _rep2(i, a, b) for(int i = (int)(a); i < (int)(b); i++)
#define rep(...) GET_MACRO(__VA_ARGS__, _rep2, _rep)(__VA_ARGS__)
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
using i64 = long long;
template<class T, class U>
bool chmin(T& a, const U& b) { return (b < a) ? (a = b, true) : false; }
template<class T, class U>
bool chmax(T& a, const U& b) { return (b > a) ? (a = b, true) : false; }

template<typename T>istream& operator>>(istream&i,vector<T>&v){rep(j,v.size())i>>v[j];return i;}
template<typename T>string join(vector<T>&v){stringstream s;rep(i,v.size())s<<' '<<v[i];return s.str().substr(1);}
template<typename T>ostream& operator<<(ostream&o,vector<T>&v){if(v.size())o<<join(v);return o;}
template<typename T>string join(vector<vector<T>>&vv){string s="\n";rep(i,vv.size())s+=join(vv[i])+"\n";return s;}
template<typename T>ostream& operator<<(ostream&o,vector<vector<T>>&vv){if(vv.size())o<<join(vv);return o;}

int main()
{
    cin.tie(nullptr);
    ios::sync_with_stdio(false);
    int n, m;
    cin >> n >> m;
    vector<int> o(n);
    cin >> o;
    vector edge(n, vector<int>());
    vector<int> cnt(n);
    rep(i, m)
    {
        int a, b;
        cin >> a >> b;
        a--, b--;
        if (o[a] > o[b]) swap(a, b);
        if (o[a] < o[b]) edge[a].push_back(b), cnt[b]++;
    }
    vector<int> lamp(n, 0);
    int k;
    cin >> k;
    rep(i, k)
    {
        int b;
        cin >> b;
        b--;
        lamp[b] = 1;
    }
    queue<int> que;
    rep(i, n) if (!cnt[i]) que.push(i);
    vector<int> ans;
    while (!que.empty())
    {
        auto now = que.front();
        que.pop();
        if (lamp[now])
        {
            ans.push_back(now + 1);
        }
        for (auto e: edge[now])
        {
            cnt[e]--;
            if (lamp[now]) lamp[e] = !lamp[e];
            if (!cnt[e]) que.push(e);
        }
    }
    cout << ans.size() << endl;
    rep(i, ans.size()) cout << ans[i] << "\n";
}