#include <cstdio>

int main (void)
{
	std::freopen("tije.in","r",stdin);
	std::freopen("tije.out","w",stdout);
	int n;
	std::scanf("%d",&n);
	int a, b, c;
	for (a = 1 ; a < n ; ++a)
	{
		for (b = n ; b ; --b)
		{
			for (c = 1 ; c <= a ; ++c)
				std::printf("%d %d\n",b,b + 1);
		}
		for (c = 1 ; c <= a ; ++c)
				std::printf("%d 1\n",n + 1);
	}
	std::fclose(stdin);
	std::fclose(stdout);
	return 0;
}