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

return 0;
}