def convArabicToOrdLetter(arabicNum, lowerCase=0):
    """
    Convert the number to the corresponding letter, indexing the alphabet where A is 1
    If lowerCase == 1 then the base letter corresponding to 1 is "a" (lower case alpha)
    """
    if arabicNum > 26:
        raise ValueError("Overflow")
    if lowerCase ==1:
        baseNum = ord("a")-1
    else:
        baseNum = ord("A")-1
    return chr(arabicNum + baseNum)