from collections import deque

N, M = map(int, input().split())
Edge = [[] for _ in range(N)]
for _ in range(M):
    u, v = map(int, input().split())
    u -= 1
    v -= 1
    Edge[u].append(v)
    Edge[v].append(u)
K = int(input())
if K > 0:
    A = set(list(map(int, input().split())))
else:
    A = set()
dist = [[-1] * N for _ in range(5)]
dist[0][0] = 0
q = deque([(0, 0)])
while q:
    k, v = q.popleft()
    for to in Edge[v]:
        if to + 1 in A:
            if 0 <= k <= 3:
                if dist[k + 1][to] != -1:
                    continue
                dist[k + 1][to] = dist[k][v] + 1
                q.append((k + 1, to))
        else:
            if dist[0][to] != -1:
                continue
            dist[0][to] = dist[k][v] + 1
            q.append((0, to))
ans = 1 << 60
for k in range(5):
    if dist[k][-1] != -1:
        ans = min(ans, dist[k][-1])
if ans == 1 << 60:
    ans = -1
print(ans)