      PROGRAM Battle
      IMPLICIT NONE
      integer :: a,b,c,d
      
      read*,a,b,c,d
      
      do while( .true. )
        a = a - d
        c = c - b
        
        if( c<=0 )then
          print*,'Yes';stop
        end if
        
        if( a<=0 )then
          print*,'No';stop
        end if
      end do
      
      
      
      
      
      END PROGRAM