#include <cassert>
#include <cstdio>

using namespace std;

int main(){
    assert(freopen("tije.in", "r", stdin));
    assert(freopen("tije.out", "w", stdout));

    int n;
    assert(scanf(" %d ", &n));
    for (int i= n-1; i>0; --i){
        for (int j= n; j>0; --j){
            for (int k= 1; k<=i; ++k){
                printf("%d %d\n", j, j+1);
            }
        }
        for (int j= 1; j<=i; ++j){
            printf("%d 1\n", n+1);
        }
    }
    return 0;
}