#include <stdio.h>
#include <stdlib.h>
long long v[1000001];
int main()
{   FILE*fi,*fout;
    long long s;
    int i,j,n;
    fi=fopen("fractii.in" ,"r");
    fout=fopen("fractii.out" ,"w");
    fscanf(fi,"%d",&n);
    for(i=1;i<=n;i++)
      v[i]=i-1;
    for(i=2;2*i<=n;i++)
       for(j=2*i;j<=n;j=j+i)
          v[j]=v[j]-v[i];
    s=0;
    for(i=1;i<=n;i++)
        s=s+v[i];
    fprintf(fout,"%lld" ,s*2+1);
    fclose(fi);
    fclose(fout);
    return 0;
}