#include <stdio.h>

int main()
{
	int N, i, j, k;

	freopen("tije.in", "r", stdin);
	freopen("tije.out", "w", stdout);

	scanf("%d", &N);

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

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

return 0;
}