#line 2 "/home/snow/competitive-programming/competitive-programming-library/snow/template.hpp"
#pragma GCC target("avx2")
#pragma GCC optimize("O3")
#pragma GCC optimize("unroll-loops")
#include <bits/stdc++.h>

constexpr long long INF = 1LL << 60;
constexpr long double PI = 3.141592653589;

#define rep(i, n) for (ll i = 0; i < (n); ++i)
#define rep1(i, n) for (ll i = 1; i <= (n); ++i)
#define rrep(i, n) for (ll i = (n - 1); i >= 0; --i)
#define ALL(obj) (obj).begin(), (obj).end()
#define RALL(obj) (obj).rbegin(), (obj).rend()
#define pb push_back
#define to_s to_string
#define len(v) (ll) v.size()
#define debug(x) cout << #x << ": " << (x) << '\n'

using namespace std;

typedef long long ll;
typedef unsigned long long ull;
typedef long double ld;
typedef pair<ll, ll> P;
typedef tuple<ll, ll, ll> tpl;

template <typename T = ll>
using vec = vector<T>;

template <typename T = ll>
using vec2 = vector<vector<T>>;

template <typename T = ll>
using vec3 = vector<vector<vector<T>>>;

template < typename T >
inline bool chmax(T &a, const T &b) {
    if (a < b) {
        a = b;
        return 1;
    }
    return 0;
}

template < typename T >
inline bool chmin(T &a, const T &b) {
    if (b < a) {
        a = b;
        return 1;
    }
    return 0;
}
#line 4 "/home/snow/competitive-programming/competitive-programming-library/snow/io/setup.hpp"

namespace snow{

struct IoSetup {
    IoSetup() {
        std::cin.tie(nullptr);
        std::ios::sync_with_stdio(false);
        std::cout << std::fixed << std::setprecision(10);
    }
} iosetup;

}
#line 5 "/home/snow/competitive-programming/competitive-programming-library/snow/io/helper.hpp"

template< typename T1, typename T2 >
std::ostream &operator << (std::ostream &os, const std::pair< T1, T2 > &p) {
    os << p.first << " " << p.second;
    return os;
}

template< typename T1, typename T2 >
std::istream &operator >> (std::istream &is, std::pair< T1, T2 > &p) {
    is >> p.first >> p.second;
    return is;
}

template< typename T1, typename T2, typename T3 >
std::ostream &operator << (std::ostream &os, const std::tuple< T1, T2, T3 > &t) {
    auto &[a, b, c] = t;
    os << a << " " << b << " " << c;
    return os;
}

template< typename T1, typename T2, typename T3 >
std::istream &operator >> (std::istream &is, std::tuple< T1, T2, T3 > &t) {
    auto &[a, b, c] = t;
    is >> a >> b >> c;
    return is;
}

template< typename T >
std::ostream &operator << (std::ostream &os, const std::vector< T > &v){
    for (int i = 0; i < (int)v.size(); ++i) {
        os << v[i] << (i + 1 != v.size() ? " " : "");
    }
    return os;
}

template< typename T >
std::istream &operator >>  (std::istream &is, std::vector< T > &v){
    for(T &in : v) is >> in;
    return is;
}

template< typename T >
std::ostream &operator << (std::ostream &os, const std::set< T > &st){
    int ct = 0;
    for(auto& s : st) os << s << (++ct != st.size() ? " " : "");
    return os;
}

template<class... T>
void input(T&... a){
    (std::cin >> ... >> a);
}

void print() {
    std::cout << '\n';
}
template<class T, class... Ts>
void print(const T& a, const Ts&... b){
    std::cout << a;
    (std::cout << ... << (std::cout << ' ', b));
    std::cout << '\n';
}

int drop() {
    std::cout << '\n';
    exit(0);
}
template<class T, class... Ts>
int drop(const T& a, const Ts&... b){
    std::cout << a;
    (std::cout << ... << (std::cout << ' ', b));
    std::cout << '\n';
    exit(0);
}
#line 4 "main.cpp"
using namespace snow;

// #include "snow/algorithm/binary-search.hpp"

// #include "atcoder/modint"
// using namespace atcoder;
// using mint = modint1000000007;

#line 2 "/home/snow/competitive-programming/competitive-programming-library/snow/graph/graph"

#line 2 "/home/snow/competitive-programming/competitive-programming-library/snow/graph/template.hpp"

#line 5 "/home/snow/competitive-programming/competitive-programming-library/snow/graph/template.hpp"

namespace snow {

/**
 * @brief Graph template
 */
template < typename T >
struct Graph {
    struct Edge {
        int to;
        T weight;
        Edge() : to(0), weight(0) {}
        Edge(int to, T weight) : to(to), weight(weight) {}
    };
    using Edges = std::vector<Edge>;

    const T INF = std::numeric_limits<T>::max();
    std::vector<Edges> G;

    Graph() : G() {}
    
    Graph(int n) : G(n) {}

    Edges& operator[](int k) {
        return G[k];
    }
    const Edges& operator[](int k) const {
        return G[k];
    }

    size_t size() const{
        return G.size();
    }

    void add_edge(int a, int b, T w = 1){
        G[a].emplace_back(b, w);
        G[b].emplace_back(a, w);
    }

    void add_directed_edge(int a, int b, T w = 1){
        G[a].emplace_back(b, w);
    }

    void add_arrow(int a, int b, T w = 1){
        add_directed_edge(a, b, w);
    }

    //Dijkstra
    std::vector<T> dijkstra(int s) const;

    //Bellman-Ford
    std::vector<T> bellman_ford(int s) const;

    //Warshall-Floyd
    std::vector<std::vector<T>> warshall_floyd() const;

    //Topological sort
    std::vector<int> topological_sort() const;
};

} // namespace snow
#line 2 "/home/snow/competitive-programming/competitive-programming-library/snow/graph/shortest-path/bellman-ford.hpp"

#line 4 "/home/snow/competitive-programming/competitive-programming-library/snow/graph/shortest-path/bellman-ford.hpp"

#line 6 "/home/snow/competitive-programming/competitive-programming-library/snow/graph/shortest-path/bellman-ford.hpp"

namespace snow{

/**
 * @brief Bellman-Ford
 * 
 * @param s 
 */
template < typename T >
std::vector<T> Graph<T>::bellman_ford(int s) const{
    std::vector<T> dist(G.size(), INF);
    dist[s] = 0;
    for(int i = 0; i < (int)G.size(); ++i){
        for(int j = 0; j < (int)G.size(); ++j){
            for(auto& e : G[j]){
                if(dist[j] == INF) continue;
                if(dist[e.to] > dist[j] + e.weight){
                    dist[e.to] = dist[j] + e.weight;
                    if(i == ((int)G.size() - 1)) return {};
                }
            }
        }
    }
    return dist;
}

}
#line 2 "/home/snow/competitive-programming/competitive-programming-library/snow/graph/shortest-path/dijkstra.hpp"

#line 5 "/home/snow/competitive-programming/competitive-programming-library/snow/graph/shortest-path/dijkstra.hpp"

#line 7 "/home/snow/competitive-programming/competitive-programming-library/snow/graph/shortest-path/dijkstra.hpp"

namespace snow{

/**
 * @brief Dijkstra
 * 
 * @param s 
 */
template < typename T >
std::vector<T> Graph<T>::dijkstra(int s) const{
    std::priority_queue<std::pair<T, int>, std::vector<std::pair<T, int>>, std::greater<>> que;
    std::vector<T> dist(G.size(), INF);
    dist[s] = 0;
    que.emplace(dist[s], s);

    while(!que.empty()){
        auto [cost, idx] = que.top();
        que.pop();
        if(dist[idx] < cost) continue;
        for(auto &e : G[idx]){
            auto next_cost = cost + e.weight;
            if(dist[e.to] <= next_cost) continue;
            dist[e.to] = next_cost;
            que.emplace(dist[e.to], e.to);
        }
    }
    return dist;
}

}
#line 2 "/home/snow/competitive-programming/competitive-programming-library/snow/graph/shortest-path/warshall-floyd.hpp"

#line 4 "/home/snow/competitive-programming/competitive-programming-library/snow/graph/shortest-path/warshall-floyd.hpp"

#line 6 "/home/snow/competitive-programming/competitive-programming-library/snow/graph/shortest-path/warshall-floyd.hpp"

namespace snow{

/**
 * @brief Warshall-Floyd
 * 
 * @tparam T 
 */
template < typename T >
std::vector<std::vector<T>> Graph<T>::warshall_floyd() const{
    int N = G.size();
    std::vector<std::vector<T>> d(N, std::vector<T>(N, INF));
    
    for(int i = 0; i < N; ++i) d[i][i] = 0;

    for(int i = 0; i < N; ++i) for(auto &e : G[i]) d[i][e.to] = e.weight;

    for(int k = 0; k < N; ++k){
        for(int i = 0; i < N; ++i){
            for(int j = 0; j < N; ++j){
                if(d[i][k] == INF or d[k][j] == INF) continue;

                d[i][j] = std::min(d[i][j], d[i][k] + d[k][j]);
            }
        }
    }
    return d;
 
}

}
#line 2 "/home/snow/competitive-programming/competitive-programming-library/snow/graph/topological-sort.hpp"

#line 5 "/home/snow/competitive-programming/competitive-programming-library/snow/graph/topological-sort.hpp"

#line 7 "/home/snow/competitive-programming/competitive-programming-library/snow/graph/topological-sort.hpp"

namespace snow {

/**
 * @brief Topological Sort
 * 
 */
template < typename T >
std::vector<int> Graph<T>::topological_sort() const {
    int N = G.size();
    std::vector<int> ind(N, 0);
    
    for(int i = 0; i < N; ++i) for (auto &e : G[i]) ind[e.to]++;
    
    std::queue<int> que;
    for(int i = 0; i < N; ++i) if (ind[i] == 0) que.push(i);

    std::vector<int> ans;
    while(!que.empty()){
        int now = que.front();
        que.pop();
        ans.emplace_back(now);

        for(auto& e : G[now]) {
            ind[e.to]--;
            if(ind[e.to] == 0) que.push(e.to);
        }
    }

    if ((int)ans.size() != N) return {};
    return ans;
}

}
#line 13 "main.cpp"

int main() {
    ll N, M;
    cin >> N >> M;
    vec<> A(N);
    cin >> A;

    Graph<ll> G(N);
    rep(i, M){
        ll u, v;
        cin >> u >> v;
        --u, --v;
        if(A[u] < A[v]) G.add_directed_edge(u, v);
        if(A[u] > A[v]) G.add_directed_edge(v, u);
    }

    ll K;
    cin >> K;
    vec<> state(N);
    rep(i, K){
        ll b;
        cin >> b;
        --b;
        state[b] = 1;
    }

    auto ret = G.topological_sort();

    ll ans = 0;
    vec<> res;

    for(auto r : ret){
        if(state[r]){
            ++ans, res.pb(r + 1);
            state[r] = 0;
            for(auto e : G[r]) state[e.to] = !state[e.to];
        }
    }

    rep(i, N){
        if(state[i]) drop(-1);
    }

    
    print(ans);
    for(auto r : res) print(r);

    return 0;
}