def main():
    n, m, k = map(int, input().split())
    a = [int(i) for i in input().split()]
    # roads = [list(map(int, input().split())) for _ in range(m)]

    voisins = {i:set() for i in range(1, n+1)}

    A = set(a) # pour les test d'appartenance
    special = False
    for _ in range(m):
        x, y = map(int, input().split())
        voisins[x].add(y)
        voisins[y].add(x)
        if not special and (x in A and y in A):
            special = True


    def distance(source, dist):
        """calculer la distance d'un sommet à tous les autres"""
        non_vus = set((i+1 for i in range(n) if i+1 != source))
        queue = [source]
        dist[source] = 0
        while queue != []:
            nextQ = []
            while queue != []:
                s = queue.pop()
                for v in voisins[s]:
                    if v in non_vus:
                        non_vus.remove(v)
                        nextQ.append(v)
                        dist[v] = dist[s]+1
            queue = nextQ
    
    dist_n = [0 for _ in range(n+1)]
    dist_1 = [0 for _ in range(n+1)]
    distance(n, dist_n)
    distance(1, dist_1)

    if special:
        return dist_n[1] # On ne rajoute rien

    # On regarde lequel ajouter
    a.sort(key=lambda x: dist_1[x]-dist_n[x])
    sp_count = len(a)
    b = [dist_n[a[-1]] for i in range(sp_count)]
    for sp in range(1, sp_count):
        b[sp_count-1-sp] = max(b[sp_count-sp], dist_n[a[sp_count-sp]])

    return min(
        dist_1[n],
        max((dist_1[a[i]]+b[i] for i in range(0, len(a)-1)))+1
    )

print(main())