Hanoi

def hanoi(n,A,C,B):
#@param:
#   n: int, number of rings;
#   A: str, initial pole;
#   C: str, destination pole;
#   B: str, empty pole;
    if n==1:
        print("Move ring from",A,"to",C)
    else:
        hanoi(n-1,A,B,C)
        print("Move ring from",A,"to",C)
        hanoi(n-1,B,C,A)