#include <fstream>

using namespace std;

fstream f;
fstream g;
int n;
int i,j;
int a[1000001];
long sum;
int k;
int primes[]={2,3,5,7,11,13,17,19,23,29,
31,37,41,43,47,53,59,
61,67,71,73,79,83,89,
97,101,103,107,109,113,
127,131,137,139,149,
151,157,163,167,173,179,
181,191,193,197,199,
211,223,227,229,233,239,
241,251,257,263,269,
271,277,281,283,293,
307,311,313,317,
331,337,347,349,353,359,
367,373,379,383,389,
397,401,409,419,
421,431,433,439,443,449,
457,461,463,467,479,
487,491,499,503,509,
521,523,
541,547,557,563,569,
571,577,587,593,599,
601,607,613,617,619,
631,641,643,647,653,659,
661,673,677,683,
691,701,709,719,
727,733,739,743,
751,757,761,769,773,
787,797,809,
811,821,823,827,829,839,
853,857,859,863,
877,881,883,887,
907,911,919,929,
937,941,947,953,
967,971,977,983,
991,997,1009};

int y;

int main()
{
   f.open("fractii.in",fstream::in);
   g.open("fractii.out",fstream::out);
   f >> n;
   sum=n;
   for(i=2;i<=n;i++)
   {
	  for(j=0;j<78498;j++)
	    if(i%primes[j]==0){
		  k=primes[j];
		  
	      for(y=i+k;y<=n;y+=k)
		     a[i]++,a[y]++;
		}
		else
		  if(primes[j]>i)
			   break;
	   sum = sum + n-a[i]-1;
   }
   g <<  sum << "\n";
   f.close();
   g.close();
 
	
	return 0;
}