#include <cstdio>
#include <iostream>
#include <bitset>
#define nmax 10000
using namespace std;

int n;
int phi[nmax];

int main()
{
    long long sol=0;
    int i;
    freopen("fractii.in","r",stdin);
    freopen("fractii.out","w",stdout);
    scanf("%d",&n);
    for (i = 1; i <= n; ++i)
        phi[i] = i-1;
    for (i = 2; i <= n; ++i)
        for (int j = 2*i; j <= n; j += i)
            phi[j] -= phi[i];
    for(i=1;i<=n;i++) sol+=phi[i];
    sol*=2;
    sol+=1;
    printf("%lld\n",sol);
    fclose(stdin);
    fclose(stdout);
    return 0;
}