#include <iostream>
#include <stdio.h>

using namespace std;

int main()
{
	int n, i, j;
	long long numere = 0 ;
	int vec[1000000];
	
	FILE * fin = fopen("fractii.in", "r");
	FILE * fout = fopen("fractii.out", "w");

	i = fscanf(fin, "%d", &n);

	for ( i = 1; i <= n; i++ )
		vec[i] = i-1;

	for ( i = 1; i <= n; i++ )
	{
		for ( j = 2 * i ; j<=n; j += i)
			vec[j] -= vec[i];
		numere += vec[i];
	}

	fprintf(fout, "%lld", numere * 2 + 1);

	fclose(fin);
	fclose(fout);

	return 0;
}