#include <fstream>
#include <math.h>
using namespace std;
FILE*fin=fopen("fractii.in","r");
FILE*fout=fopen("fractii.out","w");
int main()
{
    int n,i,j,tot[1000000];
    long long fractii;
    fscanf(fin,"%d",&n);
    tot[0]=1;
    for (i=1;i<=n;i++)
        tot[i]=i-1;
    for (i=2;i<=n;i++)
    {
        for (j=2*i;j<=n;j+=i)
            tot[j]-=tot[i];
    }
    fractii=0;
    for (i=1;i<=n;i++)
    {
        fractii+=tot[i];
    }
    fractii=fractii*2+1;
    fprintf(fout,"%d",fractii);
}