#include <iostream>
#include <stdio.h>

using namespace std;

int n;

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

	scanf("%d\n", &n );

	for ( int i = n-1; i > 0; i-- ) {
		for ( int j = 1; j <= n; j++ ) 
			for ( int k = 1; k <= i; k++ ) 
				if ( j == 1 ) printf("1 %d\n", n+1 );
				else printf("%d %d\n", j, j-1 );
		for ( int k = 1; k <= i; k++ )
			printf("%d %d\n", n+1,n );
	}	

	fclose(stdin);
	fclose(stdout);

	return 0;
}