from collections import deque
import sys
import os


IS_LOCAL = os.environ.get("LOCAL") == "true"


def debug(*args, sep=" ", end="\n", flush=False) -> None:
    if IS_LOCAL:
        print(*args, sep=sep, end=end, file=sys.stderr, flush=flush)


def yn(flg: bool) -> bool:
    print('Yes' if flg else 'No')
    return flg


def gcd(a, b):
    a = abs(a); b = abs(b)
    if a < b: a, b = b, a
    while b > 0:
        a, b = b, a % b
    return a


def lcm(a, b):
    return a * b // gcd(a, b)


def main():
    readline = sys.stdin.readline

    N, M = map(int, readline().split())
    L = 5
    G = [[] for _ in range(N)]
    for _ in range(M):
        u, v = map(lambda x: int(x) - 1, readline().split())
        G[u].append(v)
        G[v].append(u)
    int(input())
    A = list(map(lambda x: int(x) - 1, readline().split()))
    Y = [False] * N
    for a in A:
        Y[a] = True

    def encode(l, i):
        return l * N + i

    q = deque()
    seen = set()
    q.append((0, 0, 0))
    seen.add(0)
    while q:
        d, l, i = q.popleft()
        if i == N - 1:
            print(d)
            return
        for j in G[i]:
            if Y[j]:
                ll = l + 1
            else:
                ll = 0
            if ll >= L:
                continue
            xx = encode(ll, j)
            if xx in seen:
                continue
            seen.add(xx)
            q.append((d + 1, ll, j))
    print(-1)


if __name__ == "__main__":
    main()