N=int(input())
if N==2:
  print('?',1,flush=True)
  print(1)
  ans,pos=map(int,input().split())
  print('!',ans,flush=True)
  exit()
print('?',2,flush=True)
print(1,N)
ans,pos=map(int,input().split())
z=ans
if ans==-1:
  print('?',1,flush=True)
  print(1)
  ans,pos=map(int,input().split())
  print('!',ans,flush=True)
  exit()
p=[1]
print(p[1])
print('?',1,flush=True)
print(N)
ans2,pos2=map(int,input().split())
if pos2==1:
  print('!',ans2,flush=True)
else:
  print('!',z-ans2,flush=True)