N,M = map(int,input().split())
UV = [list(map(int,input().split())) for _ in range(M)]
K = int(input())
if K:
    A = set([i-1 for i in list(map(int,input().split()))])
else:
    A = []

E = [[] for _ in range(N)]
for u, v in UV:
    u -= 1
    v -= 1
    E[u].append(v)
    E[v].append(u)
V = [5] * N
V[0] = 0
Q = [0]
Q2 = []
cnt = 0
st = False
while Q:
    while Q:
        x = Q.pop()
        if x == N - 1:
            st = False
            break
        for y in E[x]:
            if y in A:
                tmp = V[x] + 1
            else:
                tmp = 0
            if V[y] > tmp:
                V[y] = tmp
                if V[y] < 5:
                    Q2.append(y)
    if st:
        break
    Q,Q2 = Q2,Q
    cnt += 1
if V[N-1] < 5:
    print(cnt - 1)
else:
    print(-1)