题解 | #统计每个月兔子的总数#

class Animal():
    # 使用静态方法，下面调用不用实例化
    @staticmethod
    def rabbit(num):
        try:
            list1 = []
            for i in range(num):
                # print(i)
                if i<2:
                    j=1
                    list1.append(j)
                else:
                    j = list1[i-2]+list1[i-1]
                    list1.append(j)
            print(list1[-1])
        except Exception as e:
            print("程序执行出错{}".format(e))
if __name__ == '__main__':
    num = int(input())
    Animal.rabbit(num)