import sys
sys.setrecursionlimit(10**7)
def ii(): return int(input())
def ist(): return input().split()
def mi(d=0): return map(lambda x:int(x)-d,input().split())
def lmi(d=0): return list(map(lambda x:int(x)-d,input().split()))
INF = float("inf")
def answer(s):
  print(s)
  exit()
################################################
n,m = mi()
g = [[] for _ in range(n)]
for _ in range(m):
  u,v = mi(1)
  g[u].append(v)
  g[v].append(u)

k = ii()
if k:
  a = set(mi(1))
else:
  a = []

visit = [[False]*n for _ in range(4)]
visit.append([True]*n)
que = [(0,0)]
ans = 0
while que:
  ans += 1
  nq = []
  for qi,qc in que:
    for gi in g[qi]:
      if gi == n-1:
        answer(ans)
      else:
        if gi in a:
          count = qc+1
        else:
          count = 0
        if not visit[count][gi]:
          visit[count][gi] = True
          nq.append((gi,count))
  que = nq
print(-1)