#include <stdio.h>
int cmmdc(int a,int b)
{
    if(a%b==0) return b;
    if(b%a==0) return a;
    return cmmdc(a%b,b%a);
}
using namespace std;
int main()
{
    FILE *fin,*fout;
    fin=fopen("fractii.in","r");
    fout=fopen("fractii.out","w");
    long int n;
    fscanf(fin,"%li",&n);
    long int a[n+1];
    a[1]=1;
    for(int i=2;i<=n;i++)
    {
        a[i]=a[i-1]+2;
        for(int j=2;j<i;j++)
        {
            if(cmmdc(i,j)==1) a[i]+=2;
        }
    }
    fprintf(fout,"%li",a[n]);
}