program main
    implicit none
    real(8) x, y, z, v, vmax
    real(8) xmax, ymax, zmax
    integer i, j, L

    read(*,*) L 
    vmax = 0.0

    do i = 1, 100
        x = real(L)/100.0*real(i)
        do j = 1, 100
            y = (real(L) - x)/100.0*real(j)
            z = real(L) - x - y
            v = x*y*z
            if (v > vmax) then
                vmax = v
                xmax = x
                ymax = y
                zmax = z
            end if
        end do
    end do

    do i = -50, 50
        x = xmax + real(L)/10000.0*real(i)
        do j = -50, 50
            y = ymax + real(L)/10000.0*real(j)
            z = real(L) - x - y
            v = x*y*z
            if (v > vmax) then
                vmax = v
            end if
        end do
    end do

    write(*,*) vmax


end program