N,M=map(int,input().split())
g=[[] for i in range(N)]
for i in range(M):
    U,V=map(int,input().split())
    g[U-1].append(V-1)
    g[V-1].append(U-1)
K=int(input())
A=[]
if K!=0:
    A=list(map(int,input().split()))

iwai=[False for i in range(N)]
for i in A:
    iwai[i-1]=True
visited=[[10**18 for j in range(5)] for i in range(N)]
from collections import deque
q=deque([])
if iwai[0]:
    q.append([0,1])
    visited[0][1]=0
else:
    q.append([0,0])
    visited[0][0]=0
while len(q)>0:
    z_=q.popleft()
    z=z_[0]
    num=z_[1]
    for k in g[z]:
        if iwai[k] and num<=3:
            if visited[k][num+1]!=10**18:
                continue
            q.append([k,num+1])
            visited[k][num+1]=visited[z][num]+1
        elif not iwai[k]:
            if visited[k][0]!=10**18:
                continue
            q.append([k,0])
            visited[k][0]=visited[z][num]+1
if min(visited[N-1])==10**18:
    print(-1)
else:
    print(min(visited[N-1]))