#include <iostream>
#include <algorithm> // for sort, mainly
#include <vector>
#include <map>
#include <set>
#include <cmath>
#include <array>
#include <string>
#include <cstdio>
#include <iterator>
#include <unordered_set>
#include <cstdint> // for int64_t, int32_t, etc
#include <queue>
#include <stack>
#include <deque>
#include <numeric> // gcd, lcm
#include <fstream>
#include <bitset> // for bitset
#include <iomanip>
#include <cassert> // for set with custom ordering
#include <type_traits> // for set with custom ordering
#include <utility> // for swap, forward, etc
using namespace std;

#pragma GCC optimize("O2")
// #pragma GCC optimize("O1","O2","O3","Ofast","unroll-loops")
// #pragma GCC target("sse","sse2","sse3","sse4.1","sse4.2","avx","avx2","fma")

template<typename A, typename B> ostream& operator<<(ostream &os, const pair<A, B> &p) { return os << '(' << p.first << ", " << p.second << ')'; }
template<typename T_container, typename T = typename enable_if<!is_same<T_container, string>::value, typename T_container::value_type>::type> ostream& operator<<(ostream &os, const T_container &v) { os << '{'; string sep; for (const T &x : v) os << sep << x, sep = ", "; return os << '}'; }
void dbg_out() { cout << endl; }
template<typename Head, typename... Tail> void dbg_out(Head H, Tail... T) { cout << ' ' << H; dbg_out(T...); }
#ifdef LOCAL
#define dbg(...) cout << "(" << #__VA_ARGS__ << "):", dbg_out(__VA_ARGS__)
#else
#define dbg(...)
#endif

/*

notes:

int64_t
stoi(string s) -> string to int
to_string() -> int (or else) to string

vector declaration:
vector<ll> v(n, 0)
vector<vector<ll>> v(n, vector<ll>(n, 0));

{if statement} ? {truth value} : {false value}

#ifdef LOCAL
    freopen("in.txt","r",stdin);
    freopen("out.txt","w",stdout);
#endif

std::lcm(ll a, ll b), std::gcd(int a, int b)

cout << fixed << setprecision(n);

set with custom ordering
set<ll, decltype(&cmp)> qu(cmp);

*/

typedef int64_t ll;

bool check(vector<ll> &d, vector<ll> &dc, vector<ll> &kn, ll n, ll k) {

	set<ll> seendis;
	vector<ll> dch(n+1, 0);

	for(ll i = 0; i < k; i++) {
		//cerr << "\ni=" << i << "; kn[i]=" << kn[i] << "; prev=" << kn[i-1];
		
		seendis.insert(d[kn[i]]);
		dch[d[kn[i]]]++;

		if(i > 0) {
			ll diff = d[kn[i]] - d[kn[i-1]];
			if(diff != 0 && diff != 1) {
				return false;
			}
		}
	}

	//cerr << "\nseendis=" << seendis;

	for(const auto & x : seendis) {
		if(x == *seendis.begin()) {
			continue;
		}
		if(x == *seendis.rbegin()) {
			continue;
		}

		if(dch[x] != dc[x]) {
			return false;
		}
	}

	// if a distance has been seen, in the middle
	// then all of its members must be present

	return true;
}

void solve() {

	ll n, m, k;
	cin >> n >> m >> k;

	vector<vector<ll>> v(n+1);

	vector<ll> known(k, 0);
	for(ll i = 0; i < k; i++) {
		cin >> known[i];
	}

	for(ll i = 0; i < m; i++) {
		ll a, b;
		cin >> a >> b;
		v[a].push_back(b);
		v[b].push_back(a);
	}

	// minden elemre megnezzuk, ez lehet-e a kezdet
	// ennyi

	vector<ll> ans;

	for(ll i = 1; i <= n; i++) {

		//cerr << "\ni=" << i;

		vector<ll> d(n+1, 1e8);
		vector<ll> dc(n+1, 0); // distance count
		queue<ll> q;
		q.push(i);
		d[i] = 0;
		while(!q.empty()) {
			ll curr = q.front();
			q.pop();

			dc[d[curr]]++;

			for(const auto & x : v[curr]) {
				if(d[curr] + 1 < d[x]) {
					d[x] = d[curr] + 1;
					q.push(x);
				}
			}
		}	

		//cerr << "\ni=" << i << "; d=" << d;

		if(check(d, dc, known, n, k)) {
			ans.push_back(i);
		}

	}

	cout << ans.size() << "\n";
	for(const auto & x : ans)
	{
		cout << x << " ";
	}
}

int main()
{
	std::ios_base::sync_with_stdio(false);
	//cin.tie(nullptr);
	//cout.tie(nullptr);

	solve();

	return 0;
}