import string


def alpha(index):
    """
    function for taking an index and converting it to the corresponding column used by excel
    works up to column ZY (column # 701)
    """
    alphabet = list(string.ascii_lowercase)
    out = ''
    n = (index + 1) / 26
    if n != 0:
        out += alphabet[n - 1]
        out += alphabet[(index + 1) % 26 - 1]
    else:
        out = alphabet[index]
    return out