#include <iostream>
#include <fstream>
using namespace std;
int v[100],p,n,o,l;
int main()
{
    ifstream f("fractii.in");
    ofstream g("fractii.out");
    f >> n;
    v[1]=1;
    v[2]=3;
    v[3]=7;
    o=4;
    for (int i=o;i<=n;++i)
    {
        p=1;
        for (int j=2;j<i;j++)
        {
            l=0;
            for (int k=2;k<=j;++k)
                if (j%k==0 && i%k==0) l=1;
            if (l==0) p=p+1;
        }
        p=p*2;
        v[i]=v[i-1]+p;
        o=o+1;
    }
    g << v[n];
    return 0;
}