def get_corr_hex(num):
    """
    Gets correspondence between a number
    and an hexadecimal string

    Parameters
    -------------
    num
        Number

    Returns
    -------------
    hex_string
        Hexadecimal string
    """
    if num < 10:
        return str(int(num))
    elif num < 11:
        return "A"
    elif num < 12:
        return "B"
    elif num < 13:
        return "C"
    elif num < 14:
        return "D"
    elif num < 15:
        return "E"
    elif num < 16:
        return "F"