#用递归会方便一点,这写法太cao了,三个变量轮流存 class Solution: def Fibonacci(self , n: int) -> int: # write code here f1,f2,sun=1,1,0 if n==0: return 0 if n<=2: return f1 for i in range(n-2): sun=f1+f2 f1=f2 f2=sun return sun num=int(input()) s=Solution() print(s.Fibonacci(num))