#include <cstdio>
using namespace std;
int main()
{FILE*f=fopen("fractii.in","r");
FILE*g=fopen("fractii.out","w");
int s,n,i,j,nr,a[1000001]={0},k,v[1000001];
nr=0;
s=0;
fscanf(f,"%d",&n);
for(i=2; i<=n; i++)
	if(a[i]==0)
		for(j=i+i; j<=n; j=j+i)
			a[j]=1;
		k=1;
for(i=2; i<=n; i++)
	if(a[i]==0){
		v[k]=i;
		k++;
	}
for(i=2; i<=n; i++){
	nr=0;
	for(j=1; j<k; j++)
		if(i%v[j]==0)
			nr=nr+(n/v[j]);
	s=s+n-nr;
}
s=s+n;
fprintf(g,"%d",s);
}