n,m = map(int,input().split())
g = [ [] for _ in range(n+1)]
for _ in range(m):
    u,v = map(int,input().split())
    g[u] += [v]
    g[v] += [u]
k = int(input())
if k != 0:
    a = list(map(int,input().split()))
else:
    a = []
di = {}
a = set(a)
from collections import deque
d = deque()
d.append((1,0,0))
di[(1,0)] = 1
while d:
    t,k,kai = d.popleft()
    if k < 5:
        for A in g[t]:
            if A == n:
                print(kai+1)
                exit()
            if A in a:
                q = 1
            else:
                q = - k
            if (A,k+q) not in di:
                di[(A,k+q)] = 1
                d.append((A,k+q,kai+1))
print(-1)