The MU game is based on the MU puzzle described in "Godel, Escher, Bach: an Eternal Golden Braid" by Douglas R. Hofstadter. To begin the game the user must supply a character string, which consists only of the characters M, U, and I. At each stage of the game the user may apply one of the following rules to change their current string into a new string. use python
Rule 1 If the current string's last character is I, then add U onto the end of the current string.
Rule 2 If the first character of the current string is M, and the rest of the string is denoted by R (so the current string looks like MR) then the new string is MRR.