#include <cstdio>
#include <algorithm>
#include <vector>
using namespace std;


int main() {
    freopen("tije.in", "r", stdin);
    freopen("tije.out", "w", stdout);
    int n;
    scanf("%d", &n);
    for (int k = n - 1; k > 0; k--) {
        for (int i = n; i > 0; i--)
            for (int j = 0; j < k; j++)
                printf("%d %d\n", i, i + 1);
        for (int j = 0; j < k; j++)
            printf("%d 1\n", n + 1);
    }
    return 0;
}