#include <stdio.h>

int n;
int contor;

int main(void)
{

	FILE* f=fopen ("fractii.in","r");
	fscanf (f,"%d",&n);
	fclose (f);

	contor=0;

	for (int i=1;i<=n;i++)
	{
		int ln=i;

		int totient=ln;
		int p1=1;
		int p2=1;
		for (int j=2;j<=ln;j++)
		{
			if (ln%j==0)
			{
				p1=p1*(j-1);
				p2=p2*j;
			}
			while (ln%j==0)
				ln=ln/j;
		}

		totient=(totient*p1)/p2;

		contor+=totient;
	}

	contor=contor+contor-1;

	f=fopen ("fractii.out","w");
	fprintf(f,"%d",contor);
	fclose (f);

	return 0;
}