#include <iostream>
#include <fstream>
#include <cstdio>
#include <vector>
using namespace std;
vector <pair <int, int> > sol;
int main()
{
    freopen("tije.in", "r", stdin);
    freopen("tije.out", "w", stdout);
    int n;
    scanf("%d", &n);
    int last = n + 1;
    n--;
    for(int i = n; i >= 1; i--)
    {
        for(int j = n + 1; j >= 1; j--)
            for(int k = 1; k <= i; k++)
                sol.push_back(make_pair(j, j + 1));
        for(int j = 1; j <= i; j++)
            sol.push_back(make_pair(last, 1));
    }
    for(auto it : sol)
        printf("%d %d\n", it.first, it.second);
    return 0;
}