from collections import deque
N,M=map(int,input().split())
G=[[] for _ in range(N+1)]
for _ in range(M):
    U,V=map(int,input().split())
    G[U].append(V)
    G[V].append(U)
K=int(input())
A=set()
if K:A=set(map(int,input().split()))
vis=[5 for _ in range(N+1)]
Q=deque()
Q.append((1,0,0))
while Q:
    now,step,cnt=Q.popleft()
    if now not in A:
        cnt=0
    vis[now]=cnt
    if now==N:
        exit(print(step))
    for nxt in G[now]:
        if cnt==4:
            if nxt in A:continue
            else:
                if cnt+1>=vis[nxt]:continue
                Q.append((nxt,step+1,cnt+1))
        else:
            if cnt+1>=vis[nxt]:continue
            Q.append((nxt,step+1,cnt+1))
print(-1)