import sys
input=lambda: sys.stdin.readline().rstrip()
l,r=10,10**9
ct=0
while r-l>1:
  mid=(l+r)//2
  print("? "+str(max(0,mid-ct)),flush=True)
  ct+=1
  ans=int(input())
  if ans==0:
    print("! "+str(max(0,mid-ct)),flush=True)

    break
  elif ans==1:
    l=mid
  else:
    r=mid
else:
  print("? "+str(max(0,r-ct)),flush=True)
  ct+=1
  if ans==0:
    print("! "+str(max(0,r-ct)),flush=True)
  else:
    print("! "+str(max(0,l-ct)),flush=True)