A developer of crossword puzzles (and other similar word games) has decided to develop a mapping between every possible word with from one to twenty characters and unique integers. The mapping is very simple, with the ordering being done first by the length of the word, and then alphabetically. Part of the list is shown below.
a 1 b 2 ... z 26 aa 27 ab 28 ... snowfall 157,118,051,752 ...
Your job in this problem is to develop a program which can translate, bidirectionally, between the unique word numbers and the corresponding words.
29697684282993 transcendental 28011622636823854456520 computationally zzzzzzzzzzzzzzzzzzzz *
elementary 29,697,684,282,993 transcendental 51,346,529,199,396,181,750 prestidigitation 28,011,622,636,823,854,456,520 computationally 232,049,592,627,851,629,097 zzzzzzzzzzzzzzzzzzzz 20,725,274,851,017,785,518,433,805,270