#include <cstdio>

int n;

int mod(int x)
{
	if (x > n) x -= n;
	return x;
}

int main()
{
	freopen("tije.in", "r", stdin);
	freopen("tije.out", "w", stdout);
	
	scanf("%d", &n);
	
	if (n == 2)
	{
		printf("1 3\n2 1\n3 2");
		return 0;
	}
	for (int i = n - 1; i >= 1; --i)
		for (int j = 1; j <= n; ++j)
		{
			int wh = mod(j + (n - i));
			for (int k = 1; k <= i; ++k)
				printf("%d %d\n", j, n + 1);
			printf("%d %d\n", wh, j);
			for (int k = 1; k < i; ++k)
				printf("%d %d\n", n + 1, j);
			printf("%d %d\n", n + 1, wh);
		}
}