N=int(input())

def request(k):
    print(f"? {k}", flush=True)
    return int(input())*2-k
sign = lambda x:(1 if x>0 else (0 if x==0 else -1))

ans1 = request(1)
ansnm1 = request(N-1)
if ans1==ansnm1:
    print(f"! 2 {N-1}", flush=True)
    exit()


l,r = 1,N-1
la,ra = ans1,ansnm1
while l+1<r:
    m = (l+r)//2
    ans = request(m)
    if ans==0:
        l=m
        break
    if sign(ans)*sign(la) < 0:
        r = m
        ra = ans
    else:
        l = m
        la = ans
if l <= N//2:
    print(f"! {l+1} {N}", flush=True)
else:
    print(f"! {1} {l}", flush=True)