#include <iostream>
#include <iomanip>//小数点出力用
//cout << fixed << setprecision(10) << ans;
#include <cmath>
#include <algorithm>
#include <vector>
#include <queue>
#include <stack>
#include <set>
#include <map>
#include <unordered_map>
using ll = long long;
using namespace std;
#define modPHash (ll)((1LL<<61)-1)
#define modP (ll)998244353
bool chkrng0idx(int pos, int sup) { return (0 <= pos && pos < sup); }
int clk4(int num) { return (num - 2) * (num % 2); }
void yn(bool tf) { cout << (tf ? "Yes\n" : "No\n"); }

int main() {
	ios::sync_with_stdio(false);
	cin.tie(nullptr);
	int N, M;
	cin >> N >> M;
	vector<int>nxt[250000];
	for (int i = 0;i < M;i++) {
		int U, V;
		cin >> U >> V;
		nxt[U].push_back(V);
		nxt[V].push_back(U);
	}
	ll dp[250000][6];
	for (int i = 0;i < 250000;i++) {
		for (int j = 0;j < 6;j++) {
			dp[i][j] = -1;
		}
	}
	bool iwai[250000] = { 0 };
	int K;
	cin >> K;
	while (K--) {
		int X;
		cin >> X;
		iwai[X] = 1;
	}
	dp[1][0] = 0;
	queue<pair<int,int>>Q;
	Q.push({ 1,0 });
	while (Q.size()) {
		int now = Q.front().first;
		int com = Q.front().second;
		Q.pop();
		for (int i = 0;i < nxt[now].size();i++) {
			if (iwai[nxt[now][i]]) {
				if (com != 4) {
					if (dp[nxt[now][i]][com + 1] == -1) {
						dp[nxt[now][i]][com + 1] = dp[now][com] + 1;
						Q.push({ nxt[now][i] ,com + 1 });
					}
				}
			}
			else {
				if (dp[nxt[now][i]][0] == -1) {
					dp[nxt[now][i]][0] = dp[now][com] + 1;
					Q.push({ nxt[now][i] ,0 });
				}
			}
		}
	}
	cout << dp[N][0];
	return 0;
}