#include<fstream.h>
int cmmdc(long long int a,long long int b){
	if(a<b){
		a=a+b;
		b=a-b;
		a=a-b;
	}
	while(a%b!=0 && b!=1 && a!=1){
		long long int r=a%b;
		a=b;
		b=r;
	}
	return b;
}
int main(){
	ifstream f("fractii.in");
	ofstream g("fractii.out");
	long long int i,j,n;
	f>>n;
	long long int ct=1;
	
	for(i=1;i<n;i++){
		for(j=i+1;j<=n;j++){
			if(cmmdc(i,j)==1){
				ct++;
				
			}
		}
	}
	
	g<<ct*2-1;
	f.close();
	g.close();
	return 0;
}