def ask(aa):
    print("?", len(aa), flush=True)
    print(*aa, flush=True)
    return int(input())

n = int(input())
ans = []
r = n
while 1:
    l = 0
    while l+1 < r:
        m = (l+r)//2
        aa = list(range(1, m+1))+ans[::-1]
        if ask(aa): r = m
        else: l = m
    ans.append(r)
    if ask(ans[::-1]): break

print("!",len(ans),flush=True)
print(*ans[::-1],flush=True)