// 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, s;
    for( i=2; i<=n; i++ )
         {
              s = n-1;
              for( j=2; j*j<i; j++ )
                  if( i%j == 0 ) s -= 2;
              if( j*j == i ) s--;
              k = i<<1;  // inmultire cu 2 pe biti
              for( j=3; k<=n; j++ )
                   {
                        s--;
                        k = j*i;
                   }
              nrf += s;
         }
    
    freopen( "fractii.out", "wt", stdout );
             printf( "%ld", nrf );
    fclose( stdout );
    return 0;
}