Alphabetical Increment A,B,..Z,ZA,ZB,..ZZ,ZZA

I am looking for a C# code that will take in an integer as parameter and return me a string. If 1, then A. If 2, then B. If 26, then Z. If 27, then ZA. If 28, then ZB. If 52, then ZZ. If 53, then ZZA.. And so on.

I could find only code that increments in A..Z,AA,AB..pattern over the net :-(

Can some one help me on this. Kinda urgent.