#include <stdio.h>

int n;

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