#include <stdio.h>
#include <math.h>
long i, n, s;
int main()
{
 FILE *f=fopen("ciur.in", "r");
 fscanf(f, "%ld", &n);
 fclose(f);
 s=n;
 f=fopen("ciur.out", "w");
 //if(n==2) fprintf(f,"1");
 for(i=2; i<sqrt(n); i++)
  s-=(n/i);
 fprintf(f, "%ld", s+2);
 fclose(f);

 return 0;
}