#include <stdio.h>
#include <stdlib.h>



int n,sum;
int v[10000];

int main(){
  int i,j;
  FILE* fin, *fout;
  fin=fopen("fractii.in","r");
  fscanf(fin,"%d",&n);
  fclose(fin);
  for (i=2; i<=n; i++){
      v[i] = i-1;
  }
  for (i=2; i<=n; i++)
      for(j =2*i;j<=n;j++){
           v[j] -= v[i];
      }
  for(i=2; i<=n; i ++){
      sum += v[i];
  }
  sum *=2;
  fout=fopen("fractii.out","w"); 
  fprintf(fout,"%d",sum + 1);
  fclose(fout);
  return 0;
}