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

typedef long long ll;
typedef vector<int> VI;
typedef vector<VI> VVI;
typedef vector<long long> VL;
typedef vector<vector<long long>> VVL;
typedef pair<int,int> Pair;
typedef tuple<int,int,int> tpl;

#define ALL(a)  (a).begin(),(a).end()
#define SORT(c) sort((c).begin(),(c).end())
#define REVERSE(c) reverse((c).begin(),(c).end())
#define EXIST(m,v) (m).find((v)) != (m).end()
#define LB(a,x) lower_bound((a).begin(), (a).end(), x) - (a).begin()
#define UB(a,x) upper_bound((a).begin(), (a).end(), x) - (a).begin()

#define FOR(i,a,b) for(int i=(a);i<(b);++i)
#define REP(i,n)  FOR(i,0,n)
#define RFOR(i,a,b) for(int i=(a)-1;i>=(b);--i)
#define RREP(i,n) RFOR(i,n,0)

#define en "\n"

constexpr double EPS = 1e-9;
constexpr double PI  = 3.1415926535897932;
constexpr int INF = 2147483647;
constexpr long long LINF = 1LL<<60;
constexpr long long MOD = 1000000007; // 998244353;

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

void Main(){
    int N,M,K;
    cin >> N >> M;
    VI A(N),light(N,0),deg(N,0);
    VVI edge(N);
    REP(i,N) cin >> A[i];
    while(M--){
        int u,v; cin >> u >> v; u--; v--;

        if(A[u]<A[v]) edge[u].push_back(v), deg[v]++;
        if(A[u]>A[v]) edge[v].push_back(u), deg[u]++;
    }

    cin >> K;
    while(K--){
        int b; cin >> b; b--;
        light[b] = 1;
    }

    int Z = 0;
    VI ans;
    stack<int> stk; REP(i,N) if(deg[i]==0) stk.push(i);
    while(!stk.empty()){
        int v = stk.top(); stk.pop();

        if(light[v]){
            Z++;
            ans.push_back(v+1);
            for(int to : edge[v]){
                light[to] = 1-light[to];
            }
        }

        for(int to : edge[v]){
            deg[to]--;
            if(deg[to] == 0) stk.push(to);
        }
    }

    cout << Z << en;
    for(int v : ans) cout << v << en;
    return;
}

int main(void){
    cin.tie(0);cout.tie(0);ios_base::sync_with_stdio(0);cout<<fixed<<setprecision(15);
    int t=1; //cin>>t;
    while(t--) Main();
    return 0;
}