#include <bits/stdc++.h>
#define REP(i, n) for (int i = 0; (i) < (int)(n); ++(i))
#define REP3(i, m, n) for (int i = (m); (i) < (int)(n); ++(i))
#define REP_R(i, n) for (int i = (int)(n)-1; (i) >= 0; --(i))
#define REP3R(i, m, n) for (int i = (int)(n)-1; (i) >= (int)(m); --(i))
#define ALL(x) ::std::begin(x), ::std::end(x)
using namespace std;

vector<int> solve(int n, int m, const vector<int64_t>& a, const vector<int>& u, const vector<int>& v, int k, const vector<int>& b) {
    vector<vector<int> > g(n);
    REP (i, m) {
        if (a[u[i]] < a[v[i]]) g[u[i]].push_back(v[i]);
        if (a[v[i]] < a[u[i]]) g[v[i]].push_back(u[i]);
    }
    vector<int> order(n);
    iota(ALL(order), 0);
    sort(ALL(order), [&](int x, int y) { return a[x] < a[y]; });
    vector<bool> used(n);
    for (int b_i : b) {
        used[b_i] = true;
    }
    vector<int> ans;
    for (int x : order) {
        if (used[x]) {
            ans.push_back(x);
            for (int y : g[x]) {
                used[y] = not used[y];
            }
        }
    }
    return ans;
}

// generated by oj-template v4.7.2 (https://github.com/online-judge-tools/template-generator)
int main() {
    std::ios::sync_with_stdio(false);
    std::cin.tie(nullptr);
    constexpr char endl = '\n';
    int N, M;
    cin >> N;
    cin >> M;
    vector<int64_t> A(N);
    REP (i, N) { cin >> A[i]; }
    vector<int> u(M), v(M);
    REP (i, M) { cin >> u[i] >> v[i]; -- u[i]; -- v[i]; }
    int K;
    cin >> K;
    vector<int> B(K);
    REP (i, K) { cin >> B[i]; -- B[i]; }
    auto ans = solve(N, M, A, u, v, K, B);
    cout << ans.size() << endl;
    REP (i, ans.size()) { cout << ans[i] + 1 << endl; }
    return 0;
}