Description
We say that integer x, 0 < x < p, is a primitive root modulo odd prime p if and only if the set { (xi mod p) | 1 <= i <= p-1 } is equal to { 1, …, p-1 }. For example, the consecutive powers of 3 modulo 7 are 3, 2, 6, 4, 5, 1, and thus 3 is a primitive root modulo 7.
Write a program which given any odd prime 3 <= p < 65536 outputs the number of primitive roots modulo p.

Input
Each line of the input contains an odd prime numbers p. Input is terminated by the end-of-file seperator.

Output
For each p, print a single number that gives the number of primitive roots in a single line.

Sample Input

23
31
79

Sample Output

10
8
24

Source

求模素数p的原根个数
关于原根请看这里:
原根

/*************************************************************************
    > File Name: POJ1284.cpp
    > Author: ALex
    > Mail: www.2cto.com
    > Created Time: 2015年06月04日 星期四 16时04分32秒
 ************************************************************************/

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