program main
  implicit none
  integer,parameter::limit=100
  integer::upper=10**9+1,lower,mid
  integer::i,ans,query
  integer,parameter::short=-1,long=1,same=0
  integer*8::N

  query = 99
  call ask(query)
  read *,ans

  if(ans.eq.same) then
     print '("!",i0)',query
     return
  else if(ans.eq.short) then
     query = 0
     do i=1,limit-1
        call ask(query)
        read *,ans
        if(ans.eq.same) then
           print '("!",i0)',i
           return
        end if
     end do
     print '("!",i0)',query
  end if

  lower = 100

  do i=1,limit-1
     mid = (lower+upper)/2
     query = mid-i

     call ask(query)
     read *,ans
     if(ans.eq.same) then
        print '("!",i0)',i+query
        return
     else if(ans.eq.short) then
        upper = mid
     else
        lower = mid
     end if
  end do
contains
  subroutine ask(query)
    integer::query
    print '("?",i0)',query
  end subroutine ask
end program main