#define _DEBUG
#include "bits/stdc++.h"
//#include <atcoder/all>
#define CHOOSE(a) CHOOSE2 a
#define CHOOSE2(a0,a1,a2,a3,a4,a5,x,...) x
#define debug_1(x1) cout<<#x1<<": "<<x1<<endl
#define debug_2(x1,x2) cout<<#x1<<": "<<x1<<", "#x2<<": "<<x2<<endl
#define debug_3(x1,x2,x3) cout<<#x1<<": "<<x1<<", "#x2<<": "<<x2<<", "#x3<<": "<<x3<<endl
#define debug_4(x1,x2,x3,x4) cout<<#x1<<": "<<x1<<", "#x2<<": "<<x2<<", "#x3<<": "<<x3<<", "#x4<<": "<<x4<<endl
#define debug_5(x1,x2,x3,x4,x5) cout<<#x1<<": "<<x1<<", "#x2<<": "<<x2<<", "#x3<<": "<<x3<<", "#x4<<": "<<x4<<", "#x5<<": "<<x5<<endl
#define debug_6(x1,x2,x3,x4,x5,x6) cout<<#x1<<": "<<x1<<", "#x2<<": "<<x2<<", "#x3<<": "<<x3<<", "#x4<<": "<<x4<<", "#x5<<": "<<x5<<", "#x6<<": "<<x6<<endl
#ifdef _DEBUG
#define debug(...) CHOOSE((__VA_ARGS__,debug_6,debug_5,debug_4,debug_3,debug_2,debug_1,~))(__VA_ARGS__)
#else
#define debug(...)
#endif
#define rep(index,num) for(int index=0;index<(int)num;index++)
#define rep1(index,num) for(int index=1;index<=(int)num;index++)
#define brep(index,num) for(int index=(int)num-1;index>=0;index--)
#define brep1(index,num) for(int index=(int)num;index>0;index--)
#define scan(argument) cin>>argument
#define prin(argument) cout<<argument<<endl
#define kaigyo cout<<endl
#define eps 1e-7
#define mp(a1,a2) make_pair(a1,a2)
#define ALL(a) (a).begin(),(a).end()
#define rALL(a) (a).rbegin(),(a).rend()
#define puba(a) emplace_back(a)
#define pubamp(a,b) emplace_back(mp(a,b))
typedef long long ll;
typedef long double ld;
using namespace std;
//using namespace atcoder;
typedef pair<ll,ll> pll;
typedef pair<int,int> pint;
typedef vector<int> vint;
typedef vector<ll> vll;
typedef vector<pint> vpint;
typedef vector<pll> vpll;
template<class T> bool chmax(T &a, const T &b) { if (a<b) { a=b; return 1; } return 0; }
template<class T> bool chmin(T &a, const T &b) { if (a>b) { a=b; return 1; } return 0; }
ll INFl=(ll)1e+18+1;
int INF=1e+9+1;
vint adj[100001];
bool on[100001];
int A[100001];
int main(){
	int N,M;
	scan(N>>M);
	rep(i,N) scan(A[i]);
	rep(i,M){
		int u,v;
		scan(u>>v);
		u--; v--;
		if(A[u]<A[v]) adj[u].puba(v);
		if(A[v]<A[u]) adj[v].puba(u);
	}
	priority_queue<pint> pq;
	int K;
	scan(K);
	rep(k,K){
		int u;
		scan(u);
		u--;
		on[u]=1;
		pq.push(mp(-A[u],u));
	}
	vint ans;
	while(!pq.empty()){
		int u=pq.top().second;
		pq.pop();
		if(!on[u]){
			continue;
		}
		on[u]=0;
		ans.puba(u);
		for(const auto& v:adj[u]){
			on[v]^=1;
			if(on[v]) pq.push(mp(-A[v],v));
		}
	}
	prin(ans.size());
	for(const auto& u:ans){
		prin(u+1);
	}
	return 0;
}