#include <fstream>
using namespace std;


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