#include <iostream>
#include <stdio.h>

using namespace std;
int n,rez=0;
int m[1000][1000];

FILE *in=fopen("fractii.in","r"),*out=fopen("fractii.out","w");


int main()
{
  int i,j,k;

  fscanf(in,"%d",&n);

  for(i=1;i<=n;i++)
   for(j=1;j<=n;j++)
     if(m[i][j]==0)
       {
        rez++;

        for(k=1;k<=n;k++)
          m[i*k][j*k]=1;

       }

 fprintf(out,"%d",rez);

return 0;
}