#include <fstream>
using namespace std;
ifstream fi("tije.in");
ofstream fo("tije.out");
int n,i,j,k;
int main()
{fi>>n;
for (i=n-1;i>=1;i--)
    {
    for (j=n;j>=1;j--)
            for (k=1;k<=i;k++) fo<<j<<" "<<j+1<<'\n';
    for (k=1;k<=i;k++) fo<<n+1<<" "<<1<<'\n';
    }

return 0;
}