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

	for(i=1;i<n;++i)
		printf("1 %d\n",n+1);
	for(i=2;i<=n;++i)
		printf("%d 1\n",i);
	
	for(i=2;i<n;++i){
		back(i);
	}
	printf("%d %d\n",n+1,n);
	fclose(stdin);
	fclose(stdout);
	return 0;
}