#include <iostream>
#include <fstream>

using namespace std;

int main()
{
    ifstream f("fractii.in");
    ofstream g("fractii.out");
    int N,P,Q,k;
    f>>N;
    k=0;
    for(P=1;P<=N;P++)
        for(Q=1;Q<=N;Q++)
            if(P/Q==0)
                {
                    k++;
                    cout<<P<<" "<<Q<<endl;
                }
    g<<k;
}