#include <bits/stdc++.h>
using namespace std;

#define int long long
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
#define reps(i, n) for (int i = 1; i <= (int)(n); i++)
#define all(a) (a).begin(), (a).end()
#define uniq(a) (a).erase(unique(all(a)), (a).end())
#define bit(n) (1LL << (n))
#define dump(a) cerr << #a " = " << (a) << endl
#define fin(a)                                                                                                         \
    cout << (a) << endl;                                                                                               \
    return 0
using vint = vector<int>;
using pint = pair<int, int>;
using vpint = vector<pint>;
template <typename T> using priority_queue_rev = priority_queue<T, vector<T>, greater<T>>;
constexpr double PI = 3.1415926535897932384626433832795028;
constexpr int DY[9] = {0, 1, 0, -1, 1, 1, -1, -1, 0};
constexpr int DX[9] = {1, 0, -1, 0, 1, -1, -1, 1, 0};
int sign(int a) {
    return (a > 0) - (a < 0);
}
int cdiv(int a, int b) {
    return (a - 1 + b) / b;
}
template <typename T> T sq(T a) {
    return a * a;
}
template <typename T, typename U> bool chmax(T &a, const U &b) {
    if (a < b) {
        a = b;
        return true;
    }
    return false;
}
template <typename T, typename U> bool chmin(T &a, const U &b) {
    if (b < a) {
        a = b;
        return true;
    }
    return false;
}
template <typename T, typename U> ostream &operator<<(ostream &os, const pair<T, U> &a) {
    os << "(" << a.first << ", " << a.second << ")";
    return os;
}
template <typename T> ostream &operator<<(ostream &os, const vector<T> &a) {
    os << "(";
    for (auto itr = a.begin(); itr != a.end(); itr++) {
        os << *itr << (next(itr) != a.end() ? ", " : "");
    }
    os << ")";
    return os;
}
template <typename T> ostream &operator<<(ostream &os, const deque<T> &a) {
    os << "(";
    for (auto itr = a.begin(); itr != a.end(); itr++) {
        os << *itr << (next(itr) != a.end() ? ", " : "");
    }
    os << ")";
    return os;
}
template <typename T> ostream &operator<<(ostream &os, const set<T> &a) {
    os << "{";
    for (auto itr = a.begin(); itr != a.end(); itr++) {
        os << *itr << (next(itr) != a.end() ? ", " : "");
    }
    os << "}";
    return os;
}
template <typename T> ostream &operator<<(ostream &os, const multiset<T> &a) {
    os << "{";
    for (auto itr = a.begin(); itr != a.end(); itr++) {
        os << *itr << (next(itr) != a.end() ? ", " : "");
    }
    os << "}";
    return os;
}
template <typename T, typename U> ostream &operator<<(ostream &os, const map<T, U> &a) {
    os << "{";
    for (auto itr = a.begin(); itr != a.end(); itr++) {
        os << *itr << (next(itr) != a.end() ? ", " : "");
    }
    os << "}";
    return os;
}
struct setup {
    static constexpr int PREC = 20;
    setup() {
        cout << fixed << setprecision(PREC);
        cerr << fixed << setprecision(PREC);
    };
} setup;

signed main() {
    int n, m;
    cin >> n >> m;
    vint a(n);
    vector<pint> ai(n);
    rep(i, n) {
        cin >> a[i];
        ai[i] = {a[i], i};
    }
    vint u(m), v(m);
    vector adj(n, vint());
    rep(i, m) {
        cin >> u[i] >> v[i], u[i]--, v[i]--;
        adj[u[i]].emplace_back(v[i]);
        adj[v[i]].emplace_back(u[i]);
    }
    int k;
    cin >> k;
    vint b(k), s(n);
    rep(i, k) {
        cin >> b[i], b[i]--;
        s[b[i]] = 1;
    }
    vint ans;
    for (auto [_, i] : ai) {
        if (s[i] == 1) {
            ans.emplace_back(i);
            for (int to : adj[i]) {
                if (a[i] < a[to]) {
                    s[to] = 1 - s[to];
                }
            }
        }
    }
    cout << ans.size() << endl;
    for (int x : ans)
        cout << x + 1 << endl;
}