      program c159
      integer L,i
      real*8 a,b,c,V
      real*8 Vnew

      read(*,*)L

      Vnew = 0.D0

      do i =1,L
        a = i
        b = (L-a)/2
        c = L-b-a

        V = a*b*c
        if (V.ge.Vnew) then
        Vnew = V
        endif

      end do
        
        write(*,*)Vnew
    
    
      end program c159


      