#include <stdio.h>

using namespace std;

#define MAX 10000000

int v[MAX],n;

int main()
{
    FILE *fin,*fout;
    fin=fopen("fractii.in","r");
    fout=fopen("fractii.out","w");

    int i;
    long long k=0;

    fscanf(fin,"%d",&n);

    for(i=2;i<=n;i++)
        v[i]=i-1;

    for(i=2;i<=n;i++)
    {
        for(int j=i+i; j<=n;j+=i)
        {
            v[j]=v[j]-v[i];
        }
        k+=v[i];
    }
    fprintf(fout,"%lld",2*k+1);

    return 0;
}