#include <iostream>
#include <fstream>
#include <algorithm>

using namespace std;

int main(){
    ifstream cin("tije.in");
    ofstream cout("tije.out");
    int n;
    cin>>n;
    for(int i=1; i<n; i++)
    {
        for(int j=0; j<n-i; j++) cout<<1<<" "<<n+1<<'\n';
        for(int j=2; j<=n+1; j++)
        {
            for(int k=0; k<n-i; k++) cout<<j<<" "<<j-1<<'\n';
        }
    }
    return 0;
}