#include<fstream>
using namespace std;
ifstream f("fractii.in");
ofstream g("fractii.out");
int s[1000001],n,i,j;
long long r;
int main()
{
    for(f>>n,i=2;i<=n;++i)
        s[i]=i-1;
    for(i=2;i<=n;++i)
        for(r+=s[i],j=i<<1;j<=n;j+=i)
            s[j]-=s[i];
    g<<(r<<1)+1;
    return 0;
}