#include<stdio.h>
int i, j, k, n, x;
inline int rst(int x){
	if (x > n)
		return x-n;
	return x;
}
int main()
{
	freopen("tije.in", "rt", stdin);
	freopen("tije.out", "wt", stdout);
	
	scanf("%d", &n);
	
	for (i = 1; i < n-1; i ++){
		for (k = 1; k <= i; k ++){
			for (j = n-i; j; j --)
				printf("%d %d\n", k, n+1);
			
			x = rst(k+i);
			printf("%d %d\n", x, k);
			
			for (j = n-i-1; j; j --)
				printf("%d %d\n", n+1, k);
		}
		
		for (k = i+1; k <= n; k ++){
			for (j = n-i-1; j; j --)
				printf("%d %d\n", k, n+1);
			
			x = rst(k+i);
			printf("%d %d\n", x, k);
			
			for (j = n-i-1; j; j --)
				printf("%d %d\n", n+1, k);
		}
		
		for (j = i; j; j --)
			printf("%d %d\n", n+1, j);
	}
	
	printf("1 %d\n", n+1);
	for (i = n; i > 1; i --)
		if (i == n)
			printf("%d 1\n", i);
		else
			printf("%d %d\n", i, i+1);
		
	printf("%d 2\n", n+1);
	
	fclose(stdin);
	fclose(stdout);
	return 0;
}