import sys

n = int(input())

print('?', 1)
sys.stdout.flush()
a1 = int(input())

print('?', n - 1)
sys.stdout.flush()
an = n // 2 - int(input())

if a1 != an:
    print('!', 2, n - 1)
    exit()

left, right = 1, n
for _ in range(18):
    mid = (left + right) // 2
    print('?', mid)
    sys.stdout.flush()
    x = int(input())
    if an == 0:
        x = mid - x
    if x * 2 == mid:
        right = mid
        break
    elif x * 2 < mid:
        right = mid
    else:
        left = mid
if right >= n // 2:
    print('!', 1, right)
else:
    print('!', right + 1, n)