def int2excel_col_name(d):
    """
    >>> int2excel_col_name(1)
    'A'
    >>> int2excel_col_name(28)
    'AB'
    >>> int2excel_col_name(100)
    'CV'
    """
    s = []
    while d:
        t = (d - 1) % 26
        s.append(chr(65 + t))
        d = (d - 1) // 26
    return ''.join(reversed(s))