#include <stdio.h>
//#include <fstream>

//using namespace std;

long cmmdc(long a, long b) {
	while (a!=b) 
		if (a>b) a=a-b;
		else b=b-a;
	return a;
}

void fractie() {
	freopen("fractii.in","r",stdin);
	//ifstream f("fractii.in");
	freopen("fractii.out","w",stdout);
	//ofstream g("fractii.out");
	long i, j, nr, n, x=0;
	scanf("%d\n", &n);
	//f>>n;
	//f.close();
	nr=2*n-3;
	for (i=4 ; i<=n ; i++)
		for (j=2 ; j<=i-2 ; j++)
			if (i%j==0)
				x=0;
			else 
				if (i%2==0 && j%2==0) 
					x=0;
				else 
					if (cmmdc(i,j)!=1) x=0;
					else nr++;
	printf("%d\n",nr*2+1);
	//g<<nr*2+1;
	//g.close();
}

int main() {
	fractie();
}