#include <fstream>

using namespace std;

ifstream fin("tije.in");
ofstream fout("tije.out");

int main(){
    int n;
    fin>>n;
    for (int i= n-1; i>0; --i){
        for (int j= n; j>0; --j){
            for (int k= 1; k<=i; ++k){
                fout<<j<<" "<<j+1<<"\n";
            }
        }
        for (int j= 1; j<=i; ++j){
            fout<<n+1<<" 1\n";
        }
    }
    return 0;
}