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Time Limit: 2 s Memory Limit: 2048 MB Total points: 100

#5394. 分数

Statistics

给定一个正整数 $n$。 请找出一个分数序列 $\frac{a_i}{b_i}, i = 1 \dots k$(其中 $a_i$ 和 $b_i$ 为正整数),对于某个 $k$ 满足:

$$ \begin{cases} b_i \text{ 整除 } n, 1 < b_i < n, \text{ 对于 } i = 1 \dots k \\ 1 \le a_i < b_i, \text{ 对于 } i = 1 \dots k \\ \sum_{i=1}^{k} \frac{a_i}{b_i} = 1 - \frac{1}{n} \end{cases} $$

输入格式

输入包含一个整数 $n$ ($2 \le n \le 10^9$)。

输出格式

如果存在这样的分数序列,第一行输出 “YES”,否则输出 “NO”。 如果存在这样的序列,接下来的行应按以下格式描述该序列: 第二行包含整数 $k$ ($1 \le k \le 100\,000$),即序列中元素的个数。题目保证如果存在这样的序列,则一定存在一个长度不超过 $100\,000$ 的序列。 接下来的 $k$ 行,每行包含两个整数 $a_i$ 和 $b_i$,表示序列中的分数。

样例

输入 1

2

输出 1

NO

输入 2

6

输出 2

YES
2
1 2
1 3

说明

在第二个样例中,存在序列 $\frac{1}{2}, \frac{1}{3}$,使得 $\frac{1}{2} + \frac{1}{3} = 1 - \frac{1}{6}$。

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