from collections import deque

N, M = list(map(int,input().split()))

karipath = []

for i in range(M):
	u, v = list(map(int,input().split()))
	u -= 1
	v -= 1
	karipath.append((u,v))
	
K = int(input())

A = []

if K > 0:
	A = list(map(int,input().split()))

for i in range(K):
	A[i] -= 1
	
A = set(A)

path = []

for i in range(5 * N):
	path.append([])
	
for i in range(M):
	u, v = karipath[i]
	if v in A:
		for i in range(4):
			path[i * N + u].append((i + 1) * N + v)
	else:
		for i in range(4):
			path[i * N + u].append(v)
	if u in A:
		for i in range(4):
			path[i * N + v].append((i + 1) * N + u)
	else:
		for i in range(4):
			path[i * N + v].append(u)
			
Q = deque()

check = set()

Q.append((0,0))

check.add(0)

ans = -1

while len(Q) > 0:
	d, p = Q.popleft()
	#print(d,p)
	if p % N == N - 1:
		ans = d
		break
	for j in path[p]:
		if j not in check:
			Q.append((d + 1, j))
			check.add(j)

print(ans)