INF = 10**10
from collections import deque
N, M = map(int, input().split())
G = [list() for _ in range(N + 1)]
for i in range(M):
    u, v = map(int, input().split())
    G[u].append(v)
    G[v].append(u)

K = int(input())
iwai = [False]*(N + 1)
if K:
    A = list(map(int, input().split()))
    for a in A:
        iwai[a] = True

# 頂点拡張BFS
dist = [[INF] * (5) for _ in range(N + 1)]
# dist[pos][level]
dist[1][0] = 0
que = deque()
que.append((1, 0))
while que:
    pos, level = que.popleft()
    for nex in G[pos]:
        # nex は 岩井頂点なら、level を1つあげる
        # そうでないなら、0 にする
        if iwai[nex]:
            nexlevel = level + 1
        else:
            nexlevel = 0 
        # dist[nex][nexlevel] を短くできるならする
        if nexlevel != 5 and dist[nex][nexlevel] > dist[pos][level] + 1:
            dist[nex][nexlevel] = dist[pos][level] + 1
            que.append((nex, nexlevel))

ans = min(dist[-1])
if ans == INF:
    ans = -1
print(ans)