n,m=map(int,input().split())
es=[]
for i in range(m):
  u,v=map(int,input().split())
  u-=1
  v-=1
  es+=[(u,v),(v,u)]
k=int(input())
if k>0:
  a=list(map(int,input().split()))
else:
  a=[]
p=[0]*n
for v in a:
  p[v-1]=1
e=[[] for i in range(n*5)]
for u,v in es:
  if p[u]==1 and p[v]==1:
    for i in range(1,4):
      e[i*n+u]+=[(i+1)*n+v]
  if p[u]==1 and p[v]==0:
    for i in range(1,5):
      e[i*n+u]+=[0*n+v]
  if p[u]==0 and p[v]==1:
    e[u]+=[n+v]
  if p[u]==0 and p[v]==0:
    e[u]+=[v]
X=10**10
v=[X]*n*5
v[0]=0
q=[0]
for s in q:
  for t in e[s]:
    if v[t]==X:
      v[t]=v[s]+1
      q+=[t]
a=min(v[i*n+n-1] for i in range(5))
print(a if a<X else -1)