def num_to_char(x: int) -> str:
    """Converts a number to a character

    :param x: Number
    :type x: int
    :return: Corresponding character
    :rtype: str

    """
    if x <= 26:
        return chr(x + 64).upper()
    elif x <= 26 * 26:
        return f"{chr(x//26+64).upper()}{chr(x%26+64).upper()}"
    else:
        raise ValueError("Integer too high to be converted")