def dscp_class(bits_0_2, bit_3, bit_4):
    """
    Takes values of DSCP bits and computes dscp class

    Bits 0-2 decide major class
    Bit 3-4 decide drop precedence

    :param bits_0_2: int: decimal value of bits 0-2
    :param bit_3: int: value of bit 3
    :param bit_4: int: value of bit 4
    :return: DSCP class name
    """
    bits_3_4 = (bit_3 << 1) + bit_4
    if bits_3_4 == 0:
        dscp_cl = "cs{}".format(bits_0_2)
    elif (bits_0_2, bits_3_4) == (5, 3):
        dscp_cl = "ef"
    else:
        dscp_cl = "af{}{}".format(bits_0_2, bits_3_4)

    return dscp_cl