def funbonaqie(a):      
    if a <=0:
        return 0
    elif a==1:
        return 1
    else:
        return funbonaqie(a-1)+funbonaqie(a-2) 

a = int(input())
result = funbonaqie(a)
print(result)

采用无脑的方法:

01:如果a<=0,则返回0,如果a==1,则返回1,其他进行递归 fn = fn(n-1)+fn(n-2)

,这种方法性能很差,不过我也没想出更好的办法.