#include <cstdio>
#include <cstdlib>
int n;


void iofile(void){
	freopen("tije.in","rt",stdin);
	freopen("tije.out","wt",stdout);
	scanf("%ld",&n);
	fclose(stdin);
}

void prel(void){
	int i,j,k;
	for (i=n-1;i>=1;i--){
		for (j=n;j>=1;j--){
			for (k=1;k<=i;k++){
				printf("%ld %ld\n",j,j+1);
			}
		}
		for (k=1;k<=i;k++){
			printf("ld %ld\n",n+1,1);
		}
	}
	fclose(stdout);
}

int main(void){
	iofile();
	prel();
	return 0;
}