1 def JumpStep(n): 2     if n <= 0: 3         return 0 4     if n == 1 or n == 2: 5         return n 6  7     return (JumpStep(n-1) + JumpStep(n - 2)) 8 while 1: 9     steps = int(raw_input())10     if steps != 0:11         print "%d cases when steps are %d" % (JumpStep(steps), steps)12     else:13         break