#include <bits/stdc++.h>

using namespace std;

using ll = long long;
using ull = unsigned long long;
using ld = long double;
using P = pair<ll, ll>;
using tp = tuple<ll, ll, ll>;

template <class T>
using vec = vector<T>;
template <class T>
using vvec = vector<vec<T>>;

#define all(hoge) (hoge).begin(), (hoge).end()
#define en '\n'
#define rep(i, m, n) for(ll i = (ll)(m); i < (ll)(n); ++i)
#define rep2(i, m, n) for(ll i = (ll)(n)-1; i >= (ll)(m); --i)
#define REP(i, n) rep(i, 0, n)
#define REP2(i, n) rep2(i, 0, n)

constexpr long long INF = 1LL << 60;
constexpr int INF_INT = 1 << 25;
constexpr long long MOD = (ll)1e9 + 7;
//constexpr long long MOD = 998244353LL;
static const ld pi = 3.141592653589793L;

#pragma GCC target("avx2")
#pragma GCC optimize("O3")
#pragma GCC optimize("unroll-loops")

template <class T>
inline bool chmin(T &a, T b) {
    if(a > b) {
        a = b;
        return true;
    }
    return false;
}

template <class T>
inline bool chmax(T &a, T b) {
    if(a < b) {
        a = b;
        return true;
    }
    return false;
}

//グラフ関連
struct Edge {
    int to, rev;
    ll cap;
    Edge(int _to, ll _cap, int _rev) : to(_to), cap(_cap), rev(_rev) {}
};

typedef vector<Edge> Edges;
typedef vector<Edges> Graph;

void add_edge(Graph &G, int from, int to, ll cap, bool revFlag, ll revCap) {
    G[from].push_back(Edge(to, cap, (int)G[to].size()));
    if(revFlag)
        G[to].push_back(Edge(from, revCap, (int)G[from].size() - 1));
}

bool tsort(Graph &graph, vec<ll> &order) {
    int n = graph.size(), k = 0;
    vec<ll> in(n);
    for(auto &es : graph)
        for(auto &e : es)
            in[e.to]++;
    priority_queue<ll, vec<ll>, greater<ll>> que;
    REP(i, n)
    if(in[i] == 0)
        que.push(i);
    while(que.size()) {
        int v = que.top();
        que.pop();
        order.push_back(v);
        for(auto &e : graph[v])
            if(--in[e.to] == 0)
                que.push(e.to);
    }
    if(order.size() != n)
        return false;
    else
        return true;
}

void solve() {
    ll n, m;
    cin >> n >> m;
    vec<ll> a(n);
    REP(i, n) {
        cin >> a[i];
    }

    Graph g(n);
    REP(i, m) {
        int u, v;
        cin >> u >> v;
        u--;
        v--;
        if(a[u] < a[v])
            add_edge(g, u, v, 1, false, 1);
        else if(a[v] < a[u])
            add_edge(g, v, u, 1, false, 1);
    }

    int k;
    cin >> k;
    vec<bool> b(n, false);
    REP(i, k) {
        int bb;
        cin >> bb;
        bb--;
        b[bb] = true;
    }

    vec<ll> o;
    tsort(g, o);
    vec<ll> ans;
    REP(i, n) {
        int v = o[i];
        if(b[v]) {
            b[v] = false;
            ans.push_back(v + 1);
            for(auto e : g[v]) {
                b[e.to] = !b[e.to];
            }
        }
    }
    cout << ans.size() << en;
    for(auto i : ans)
        cout << i << en;
}

int main() {
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);

    // ll t;
    // cin >> t;
    // REP(i, t - 1) {
    //     solve();
    // }

    solve();

    return 0;
}