n = int(input())
def ask(x):
    print(f'? {x}')
    r = int(input())
    return r - (x - r)
def answer(l, r):
    print(f'! {l + 1} {r}')
    exit(0)

res0, res1 = ask(1), ask(n - 1)
if res0 == res1:
    answer(1, n - 1)

l, r = 1, n - 1  # (l, r)
while True:
    c = (l + r) // 2
    res = ask(c)
    if res == 0:
        if c <= n // 2:
            answer(c, n)
        else:
            answer(0, c)
    if res > 0 and res0 > 0 or res < 0 and res0 < 0:
        l = c
    else:
        r = c