#include <stdio.h>

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