Coprimes

Coprimes

Time Limit:250MS     Memory Limit:4096KB     64bit IO Format:%I64d & %I64u

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Description

For given integer N (1<=N<=10⁴) find amount of positive numbers not greater than N that coprime with N. Let us call two positive integers (say, A and B, for example) coprime if (and only if) their greatest common divisor is 1. (i.e. A and B are coprime iff gcd(A,B) = 1).

Input

Input file contains integer N.

Output

Write answer in output file.

Sample Input

9

Sample Output

6

#include
#include 
using namespace std;
int gcd(int a,int b)
{
     return b==0?a:gcd(b,a%b);
}
int main()
{
	int n;
	while(scanf("%d",&n)!=EOF){
		int ans=0;
		for(int i=0;i