#include <iostream>
#include <fstream>
#define nmax 1000000
using namespace std;
ifstream fin("fractii.in");
ofstream fout("fractii.out");

long a[nmax];
int main()
{long n,i,j;
long long rez=0;
fin>>n;
    for(i=2;i<=n;i++)a[i]=i-1;
    for(i=2;i<=n;i++)
        {for(j=2;i*j<=n;j++)
        a[i*j]-=a[i];
    rez+=a[i];}
fout<<2*rez+1;
}