#include<fstream.h>
#include<math.h>


int main() {
long s,n,i,j,k,m,l;
int a[10000];
ifstream f("fractii.in");
ofstream g("fractii.out");
f>>n;
s=2*n-1;
for (i=2;i<=n;i++) {
	m=1;
	for (j=2;j<=floor(sqrt(i));j++) if (i % j ==0) a[m++]=j;
	a[m]=i;
	k=(n-i)+1;
	for (j=i;j<=n;j++)
	for (l=1;l<=m;l++) if (j % a[l] == 0) {k--; break;}
	s=s+k*2;
}
g<<s;
f.close();
g.close();
return 0;
}