"""

https://yukicoder.me/problems/no/2085

これは典型！
マージソートだけど、回数足りるのか…？

"""

import sys
from sys import stdin
from collections import deque
import heapq

N = int(stdin.readline())

q = []

for i in range(N):
    heapq.heappush(q, [1,[i+1]])

while len(q) > 1:

    _,A = heapq.heappop(q)
    _,B = heapq.heappop(q)

    A = deque(A)
    B = deque(B)

    C = []

    while A and B:

        print ("?",A[0],B[0],flush=True)

        cat = int(stdin.readline())

        if cat == 1:
            C.append(A.popleft())
        else:
            C.append(B.popleft())

    while A:
        C.append(A.popleft())

    while B:
        C.append(B.popleft())

    heapq.heappush(q, [len(C),C])

print ("!")
print (len(q[0][1])-1)
print (*q[0][1])