import sys
from collections import deque, Counter
input = lambda: sys.stdin.readline().rstrip()
ii = lambda: int(input())
mi = lambda: map(int, input().split())
li = lambda: list(mi())
inf = 2 ** 63 - 1
mod = 998244353

n = ii()

def query(x):
    print('?', x, flush=True)
    p = ii()
    return 2 * p - x
def ans(l, r):
    print('!', l, r, flush=True)

a = query(1)
b = query(n - 1)
if a == b:
    ans(2, n - 1)
else:
    ng = n
    ok = 1
    for _ in range(18):
        mid = (ok + ng) // 2
        p = query(mid)
        if p == 0:
            if mid >= n // 2:
                ans(1, mid)
            else:
                ans(mid + 1, n)
            exit()
        elif p == b:
            ng = mid
        else:
            ok = mid
    if ok >= n // 2:
        ans(1, ok)
    else:
        ans(ok + 1, n)