#include <iostream>
#include <algorithm>
#include <map>
#include <set>
#include <queue>
#include <stack>
#include <numeric>
#include <bitset>
#include <cmath>

static const int MOD = 1000000007;
using ll = long long;
using u32 = unsigned;
using u64 = unsigned long long;
using namespace std;

template<class T> constexpr T INF = ::numeric_limits<T>::max() / 32 * 15 + 208;

int main() {
    int n, m;
    cin >> n >> m;
    vector<int> A(n);
    for (auto &&i : A) scanf("%d", &i);
    vector<vector<int>> G(n);
    for (int i = 0; i < m; ++i) {
        int u, v;
        scanf("%d %d", &u, &v);
        u--; v--;
        if(A[u] < A[v]) G[u].emplace_back(v);
        if(A[v] < A[u]) G[v].emplace_back(u);
    }
    vector<int> on(n);
    int k;
    cin >> k;
    for (int i = 0; i < k; ++i) {
        int x;
        scanf("%d", &x);
        on[x-1]++;
    }
    vector<int> d(n);
    for (int i = 0; i < n; ++i) {
        for (auto &&j : G[i]) {
            d[j]++;
        }
    }
    queue<int> Q;
    for (int i = 0; i < n; ++i) {
        if(!d[i]) Q.emplace(i);
    }
    vector<int> ans;
    while(!Q.empty()){
        int x = Q.front(); Q.pop();
        int ok = on[x];
        if(on[x]) on[x] = 0, ans.emplace_back(x);
        for (auto &&y : G[x]) {
            if(ok) on[y] ^= 1;
            if(!(--d[y])) Q.emplace(y);
        }
    }
    cout << ans.size() << "\n";
    for (auto &&i : ans) {
        cout << i+1 << "\n";
    }
    return 0;
}