n, m = map(int, input().split())
node = [[] for _ in range(n)]
for i in range(m):
    u, v = [int(x)-1 for x in input().split()]
    node[u].append(v)
    node[v].append(u)
k = int(input())
if k:
    C = set([int(x)-1 for x in input().split()])
    A = [1 if i in C else 0 for i in range(n)]
else:
    A = [0] * n
dp = [[-1] * 5 for _ in range(n)]
dp[0][0] = 0
from collections import deque
dq = deque([(0, 0)])
while dq:
    now, cnt = dq.popleft()
    for nxt in node[now]:
        if A[nxt]:
            ncnt = cnt+1
        else:
            ncnt = 0
        if ncnt < 5 and dp[nxt][ncnt] == -1:
            dp[nxt][ncnt] = dp[now][cnt] + 1
            dq.append((nxt, ncnt))

inf = float("INF")
ans = inf
for i in range(5):
    if dp[-1][i] != -1:
        ans = min(ans, dp[-1][i])
print(ans if ans != inf else -1)