#include <stdio.h>

FILE *in,*out;

using namespace std;

int main()
{
    in=fopen("fractii.in","rt");
    out=fopen("fractii.out","wt");
    int n,i,j,ct=0;
    fscanf(in,"%d",&n);
    int v[n-1];
    for(i=1;i<=n;++i)
        {
            v[i]=i-1;
        }
    for(i=2;i<=n;++i)
    {
        for(j=2*i;j<=n;j=j+i)
            v[j]=v[j]-v[i];
    }
    for(i=1;i<=n;i++)
    {
        ct=ct+v[i];
    }
    ct=2*ct+1;
    fprintf(out,"%d",ct);
    return 0;
}