program siax
  implicit none
  integer :: N,l,i

  real(8) :: c,d,e
  character(len=15) :: S
  read(*,*) S
  l=0
  do i=1,len_trim(S)
     if(S(i:i).eq.'o') then
        l=l+1
     endif
  enddo
  if((15-len_trim(S)+l).lt.8) then
     write(*,'(a)') 'NO'
  else
     write(*,'(a)') 'YES'
  endif
!  write(*,'(i0)') l                                                                                                                                     
end program siax

