#include<fstream.h>
 ifstream f("fractii.in");
 ofstream g("fractii.out");
 
 int main()
{
 int v[100]={0},c,n,i,j;
 f >> n;
 c = n;
 for(j=1;j<=n/2;j++)
		 v[2*j] = 1;
 for(i=3;i<=7;i=i+2)
	 for(j=2;i*j<=n;j++)
		 if(!v[i*j])
			 v[i*j] = 1;
 int c1 = 0;
 for(i = 3;i<=n;i++)
	 if(!v[i])
		 c1++;

 for(i=2;i<=n;i++)
	 if(!v[i])
		 c+=n-1;
	 else
		c+=c1+1;
		
 g <<c ;
 f.close();
 g.close();
 return 0;
}