#include <iostream>
#include <vector>

using namespace std;

int main()
{
    long int n, total, pv;
    cin >> n;
    vector<vector<int>> vec(n+1, vector<int> (n+1, 0));
    total=n*n-n+1;
    for (int i=2; i<=n; i++)
    {
        for (int j=1; j<i; j++)
        {
            pv=2;
            while (i*pv<=n && j*pv<=n && vec[i][j]==0)
            {
                vec[i*pv][j*pv]=1;
                total-=2;
                pv++;
            }
        }
    }
    cout<<total;
}