#include <fstream>

using namespace std;

long i,j,n,k;

int main()
{ ifstream f("tije.in");
  ofstream g("tije.out");
  f>>n;
  for (i=n-1;i>=1;i--) {
  for (j=n;j>=1;j--)
   for (k=1;k<=i;k++)
    g<<j<<" "<<j+1<<endl;
  for (k=1;k<=i;k++)
   g<<n+1<<" "<<1<<endl;
   g<<n+1<<" "<<1<<endl;
   g<<1<<" "<<n+1<<endl;
 }
 return 0;
}