#include<iostream>
#include<fstream>
#include<cmath>
using namespace std;

int main(){


	int n;
	ifstream in("functii.in");
	ofstream out("functii.out");
	in>>n;
	int i,j;
	int suma=0;
	int sv[100000];
	for(i=1;i<=n;i++)
		sv[i]=i-1;
	for(i=1;i<=n;i++){
		for(j=2*i;j<=n;j=j+i){
			sv[j]=sv[j]-sv[i];
		}
	}

	for(i=2;i<=n;i++)
		suma+=sv[i];
	out<<2*suma+1;
	in.close();
	out.close();
	return 0;
}