#include <stdio.h>
#include <stdlib.h>
#include <stdbool.h>
int n,i,j,nr,ciur[1000001];
int prime_intre_ele(int a, int b)
{
    while(a!=b)
    {
        if(a>b)
            a=a-b;
        else
            b=b-a;
    }
    return a;
}



int main()
{
    freopen("fractii.in", "r", stdin);
    freopen("fractii.out", "w", stdout);
    scanf("%d",&n);
    nr=2*n-1;
    for(i=2;i<=(n/2);i++)
        for(j=2;(j*i)<=n;j++)
            ciur[j*i]=1;
    for(i=2;i<=n;i++)
    {
        if(ciur[i]==0)
            nr+=(n-1)-(n/i);
        else
        {
                for(j=2;j<=n;j++)
                    if(prime_intre_ele(i,j)==1)
                        nr++;
        }
    }
    printf("%d",nr);
    return 0;
}