#include <iostream>
#include <fstream>

using namespace std;
int i,aux,prie=1;
int prime(int a,int b)
{
    prie=1;
    if(a>b)
    {
        aux=a;
        a=b;
        b=aux;
    }
    if(a!=1)
    for(i=2;i<=a;i++)
    {
        if(b%i==0&&a%i==0)prie=0;
    }
return prie;
}

int main()
{
    ifstream in("fractii.in");
    ofstream out("fractii.out");
    int n,p,q,c=0;
    in>>n;
    for(p=1;p<=n;p++)
    {
        for(q=1;q<=n;q++)
        {
            if(prime(p,q)==1)
            {
                c++;
                cout<<p<<" "<<q<<endl;
            }
        }
    }
    out<<c;
}