#include <fstream>
using namespace std;

ifstream f1 ("fractii.in"); //INTRARE
ofstream f2 ("fractii.out"); //IESIRE

int cmmdc(int a, int b)
{
    int t;
    while (b != 0)
    {
        t = b;
        b = a % b;
        a = t;
    }
    return a;
}
int main(){
	int n;
	long long s;
	f1>>n;
	s = n * 2 - 1;
	for(int i = 2; i <= n; i++){
		for(int j = i + 1; j <= n; j++){
			if(cmmdc(i,j) == 1) s += 2;
		}
	}
	f2<<(int)s<<"\n";
	return 0;
}