import sys
n = int(input())
li = [-1]*n
now=1
print("? ",now,flush=True)
q = int(input())
cri = q*2-now
li[now-1]=cri
a=cri

now=n-1
print("? ",now,flush=True)
q = int(input())
cri = q*2-now
li[now-1]=cri
b=cri

if a*b>0:
    print("!",1,n-1,flush=True)
    sys.exit()

#a*b<0
l=1
r=n-1
for i in range(18):
    lv=li[l-1]
    rv=li[r-1]

    mid = (l+r)//2
    now=mid
    print("? ",now,flush=True)
    q = int(input())
    cri = q*2-now
    li[now-1]=cri
    if cri==0:
        if mid<=n//2:
            print("!",mid,n,flush=True)
        else:
            print("!",1,mid,flush=True)
        sys.exit()
    elif cri>0:
        if lv>0:
            l=mid
        else:
            r=mid
    else:
        #cri<0
        if lv<0:
            l=mid
        else:
            r=mid