#include <iostream>
#include <cstdio>
using namespace std;
FILE*si=fopen("tije.in","r");
FILE*so=fopen("tije.out","w");
int main()
{
    int n;
    fscanf(si,"%i",&n);
    for(int i=n-1;i;--i)
    {
        for(int j=n;j;--j)
            for(int k=i;k;--k)
                fprintf(so,"%i %i\n",j,j+1);
        for(int j=i;j;--j)
            fprintf(so,"%i 1\n",n+1,1);
    }
    return 0;
}