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

void bfs(int a, vector<int> &x) {
	queue<int> q;
	q.push(a);
	x[a] = 0;
	while(q.size() != 0) {
		int v = q.front();
		q.pop();
		for(int i : g[v]) {
			if(x[i] == -1) {
				x[i] = x[v] + 1;
				q.push(i);
			}
		}
	}
}

int main() {
	int n,m,k; cin >> n >> m >> k;
	vector<int> x(0);
	g.assign(n+1, vector<int>(0));
	vector<int> ans(0);
	for(int i = 0; i < k; i++) {
		int a; cin >> a;
		x.push_back(a);
	}
	for(int i = 0; i < m; i++) {
		int a,b; cin >>a >> b;
		g[a].push_back(b);
		g[b].push_back(a);
	}
	for(int i = 1; i <= n; i++) {
		vector<int> z(n+1, -1);
		bfs(i,z);
		bool u = true;
		for(int j = 1; j < k; j++) {
			if(z[x[j]] != z[x[j-1]] && z[x[j]] != z[x[j-1]] + 1) u = false;
		}
		if(u) ans.push_back(i);
	}
	sort(begin(ans), end(ans));
	cout << ans.size() << endl;
	for(int i : ans) cout << i << " ";
}