#P2235. [HNOI2002] Kathy函数

    ID: 1209 远端评测题 1000ms 125MiB 尝试: 0 已通过: 0 难度: 8 上传者: 标签>动态规划,dp高精度2002各省省选湖南数位 dp

[HNOI2002] Kathy函数

Description

Tiger likes math very much, so he joined the school's extracurricular math club. In the club, the teacher introduced the Kathy function to Tiger, which is defined as:

$$\left\{ \begin{aligned} &f(1)=1\\ &f(3)=3\\ &f(2n)=f(n)\\ &f(4n+1)=2f(2n+1)-f(n)\\ &f(4n+3)=3f(2n+1)-2f(n) \end{aligned} \right.$$

Tiger became very interested in the Kathy function, and through studying he found that many numbers nn satisfy f(n)=nf(n)=n.

Given a number mm, he wants you to find the number of positive integers nn such that f(n)=nf(n)=n, where nmn \leq m.

Input Format

The input contains a single line with an integer mm.

Output Format

Output a single integer: the number of positive integers nn with nmn \leq m that satisfy f(n)=nf(n)=n.

5
3

Hint

Constraints

For all testdata, it is guaranteed that 1m101001 \leq m \leq 10^{100}.

Translated by ChatGPT 5