#include <stdio.h>

const int N_MAX = 128;

int N;

void solve(int inc)
{
	int i, j;

	for (i = 1; i <= inc; i ++) printf("%d %d\n", N, N + 1);
	for (i = N - 1; i >= inc; i --) {
		for (j = 1; j < inc; j ++) {
			printf("%d %d\n", i, i + 1);
		}
		printf("%d %d\n", i, N + 1);
	}

	for (i = 1; inc + i <= N; i ++) printf("%d %d\n", inc, inc + i);
	for (i = 1; i <= N; i ++) printf("%d %d\n", N + 1, inc);
}

int main()
{
	freopen("tije.in", "r", stdin);
#ifndef _SCREEN_
	freopen("tije.out", "w", stdout);
#endif

	int i;
	scanf("%d\n", &N);

	for (i = N; i >= 1; i --) printf("%d %d\n", i, N + 1);
	for (i = 1; i < N; i ++) printf("1 %d\n", i + 1);
	for (i = 1; i <= N; i ++) printf("%d %d\n", N + 1, 1);

	for (i = 2; i < N; i ++) solve(i);

	return 0;
}