#include <bits/stdc++.h>
#define nmax 1000005
using namespace std;

int n,a[nmax];

inline void Phi(int nr)
{
    int i,j;
    for(i=2;i<=nr;i++)
        a[i]=i-1;
    for(i=3;i<=nr;i++)
        for(j=i+i;j<=nr;j+=i)
            a[j]-=a[i];
}

inline int Solve()
{
    int i,sum;
    Phi(n);
    a[i]=1;
    for(i=1;i<=n;i++)
        sum+=a[i];
    sum*=2;
    sum++;
    return sum;
}

inline void Input()
{
    ifstream fin("fractii.in");
    ofstream fout("fractii.out");
    fin>>n;
    fout<<Solve()<<"\n";
    fout.close();
    fin.close();
}

int main()
{
    Input();
    return 0;
}