求最大公约数。
CODE:
/*
AUTHOR: Su Jiao
DATE: 2010-8-24
DESCRIPTION:
$DESCRIPTION
*/
#include <iostream>
using namespace std;
int main()
{
int N,answer=0;
cin>>N;
for (int i=1;i<=N;i++)
{
int a=N,b=i,t;
while (b) t=a,a=b,b=t%b;
if (a==1) answer++;
}
cout<<answer<<endl;
}