// Problema  fractii

#include <stdio.h>

int main()
{
    long n, nrf;
    freopen( "fractii.in", "rt", stdin );
             scanf( "%ld", &n );
    fclose( stdin );
    
    nrf = n;
    long i, j, k, l, s;
    for( i=2; i<=n; i++ )
         {
              s = n-1;
              for( j=2; j*j<=i; j++ )
                  if( i%j == 0 ) 
                      {
                          l = j;
                          for( k=1; l<=n; k++ )
                               {
                                    s--;
                                    l = k*j;
                               } 
                      }
              nrf += s;
         }
    
    freopen( "fractii.out", "wt", stdout );
             printf( "%ld\n", nrf );
    fclose( stdout );
    return 0;
}