program main
    implicit none
    real(8) :: X, Y, L

    read *, X
    read *, Y
    read *, L

    if (X == 0) then
        if (Y >= 0) then
            print *, ceiling(abs(Y) / L)
        else
            print *, ceiling(abs(Y) / L) + 2
        end if
    else if (Y >= 0) then
        print *, ceiling(abs(Y) / L) + 1 + ceiling(abs(X) / l)
    else
        print *, ceiling(abs(Y) / L) + 2 + ceiling(abs(X) / l)
    end if
end program main