#include <cstdio>

#define file_in "tije.in"
#define file_out "tije.out"

int n;

void citire()
{
	freopen(file_in,"r",stdin);
	freopen(file_out,"w",stdout);
	
	scanf("%d", &n);
}

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

int main()
{
	citire();
	solve();
	
	fclose(stdin);
	fclose(stdout);
	
	return 0;
	
}