"""

0 110

0 011

"""

import sys
from sys import stdin

def ask(i):

    print ("?",i,flush=True)
    cat = int(stdin.readline())
    assert cat != -1
    return cat

N = int(stdin.readline())

one = ask(1)
two = ask(2)

a1 = one
a2 = two-one
if a1 != a2:
    print ("!",1,2,flush=True)
    sys.exit()

l = 2
r = N

while r-l != 1:

    m = (l+r)//2
    get = ask(m)

    x = get-a1 #one
    y = (m-1)-x #zero

    #print (m,x,y)

    if a2 == 1:
        if x <= y:
            r = m
        else:
            l = m
    else:
        if x >= y:
            r = m
        else:
            l = m

print ("!",2,r,flush=True)