n,m=map(int,input().split())
a=[[]for i in range(n)]
for i in range(m):
	s,t=map(int,input().split())
	a[s-1].append(t-1)
	a[t-1].append(s-1)
k=int(input())
if k>0:
    b=set(map(int,input().split()))
else:
    b=set()
c=[[10**10 for _ in range(5)]for _ in range(n)]
c[0][0]=0
now={(0,0)}
while now:
	new=set()
	for i in now:
		for j in a[i[0]]:
			if j+1 in b:
				if i[1]!=4:
					if c[j][i[1]+1]==10**10:
						c[j][i[1]+1]=c[i[0]][i[1]]+1
						new.add((j,i[1]+1))
			else:
			    if c[j][0]==10**10:
			        c[j][0]=c[i[0]][i[1]]+1
			        new.add((j,0))
	now=new 
z=min(c[-1])
if z==10**10:
    print(-1)
else:
    print(z)