CF1027G.X-mouse in the Campus

省选/NOI-

通过率:0%

时间限制:1.50s

内存限制:256MB

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题目描述

The campus has mm rooms numbered from 00 to m−1m - 1. Also the xx-mouse lives in the campus. The xx-mouse is not just a mouse: each second xx-mouse moves from room ii to the room i⋅xmod  mi \cdot x \mod{m} (in fact, it teleports from one room to another since it doesn't visit any intermediate room). Starting position of the xx-mouse is unknown.

You are responsible to catch the xx-mouse in the campus, so you are guessing about minimum possible number of traps (one trap in one room) you need to place. You are sure that if the xx-mouse enters a trapped room, it immediately gets caught.

And the only observation you made is GCD(x,m)=1\text{GCD} (x, m) = 1.

校园中有 mm 个房间,编号从 00 到 m−1m - 1。此外,一只 xx-鼠生活在校园中。这只 xx-鼠并非普通老鼠:每秒,它会从房间 ii 移动到房间 i⋅xmod  mi \cdot x \mod{m}(实际上,它通过瞬移在房间之间移动,不经过任何中间房间)。xx-鼠的初始位置未知。

你负责在校园中捕获这只 xx-鼠,因此你需要估计所需放置的陷阱(每个房间最多放一个陷阱)的最小可能数量。你确信:一旦 xx-鼠进入一个布置了陷阱的房间,它将立即被捕获。

你唯一掌握的信息是 GCD(x,m)=1\text{GCD} (x, m) = 1。

输入格式

The only line contains two integers mm and xx (2≤m≤10142 \le m \le 10^{14}, 1≤x<m1 \le x \lt m, GCD(x,m)=1\text{GCD} (x, m) = 1) — the number of rooms and the parameter of xx-mouse.

唯一一行包含两个整数 mm 和 xx(2≤m≤10142 \le m \le 10^{14},1≤x<m1 \le x \lt m,GCD(x,m)=1\text{GCD} (x, m) = 1)——分别为房间数量和 xx-老鼠的参数。

输出格式

Print the only integer — minimum number of traps you need to install to catch the xx-mouse.

输出唯一的整数——为捕获 xx-鼠所需的最少陷阱数量。

输入输出样例

  • 输入#1

    4 3

    输出#1

    3
  • 输入#2

    5 2

    输出#2

    2

说明/提示

In the first example you can, for example, put traps in rooms 00, 22, 33. If the xx-mouse starts in one of this rooms it will be caught immediately. If xx-mouse starts in the 11-st rooms then it will move to the room 33, where it will be caught.

In the second example you can put one trap in room 00 and one trap in any other room since xx-mouse will visit all rooms 1..m−11..m-1 if it will start in any of these rooms.

在第一个例子中,例如,你可以在房间 00、22、33 中放置陷阱。如果 xx-mouse 从这些房间中的任意一个出发,则它将立即被捕获。如果 xx-mouse 从第 11 个房间出发,则它将移动到房间 33,并在那里被捕获。

在第二个例子中,你可以在房间 00 中放置一个陷阱,并在其余任意一个房间中再放置一个陷阱,因为若 xx-mouse 从房间 1..m−11..m-1 中的任意一个出发,它将访问所有这些房间。

输入解题思路,AI测评打分。不知道怎么写?

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