POJ 2407-Relatives(求一個整數的歐拉函數值)

POJ 2407-Relatives(求一個整數的歐拉函數值)

 

Relatives Time Limit:1000MS Memory Limit:65536KB 64bit IO Format:%I64d & %I64u Submit Status Practice POJ 2407 Appoint description: System Crawler (2015-04-04)

Description

Given n, a positive integer, how many positive integers less than n are relatively prime to n? Two integers a and b are relatively prime if there are no integers x > 1, y > 0, z > 0 such that a = xy and b = xz.

Input

There are several test cases. For each test case, standard input contains a line with n <= 1,000,000,000. A line containing 0 follows the last case.

Output

For each test case there should be single line of output answering the question posed above.

Sample Input

7
12
0

Sample Output

6
4

 

題意：給一個數n，求出不大於n且與n互素的數的個數。

 

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