from collections import deque

n, m = map(int, input().split())
edges = [[] for _ in range(n+1)]
for _ in range(m):
    u, v = map(int, input().split())
    edges[u].append(v)
    edges[v].append(u)

k = int(input())
if k != 0:
    iwai = set(list(map(int, input().split())))
else:
    iwai = set()

visited = [[-1 for _ in range(5)] for _ in range(n+1)]
queue = deque([(1, 1 if 1 in iwai else 0)])
visited[1][1 if 1 in iwai else 0] = (0, 0)

while queue:
    v, count = queue.popleft()
    if v == n:
        ans = [v]
        now_count = count
        while visited[v][now_count] != (0, 0):
            ans.append(visited[v][now_count][0])
            v, now_count = visited[v][now_count]
        
        print(len(ans) - 1)
        break
        
    for u in edges[v]:
        if u in iwai:
            new_count = count + 1
        else:
            new_count = 0
        
        if new_count >= 5:
            continue
        if visited[u][new_count] == -1:
            visited[u][new_count] = (v, count)
            queue.append((u, new_count))
else:
    print(-1)