#include <bits/stdc++.h>

using namespace std;

FILE *fin=fopen("tije.in","r");
FILE *fout=fopen("tije.out","w");

int n;

int main()
{
    int i,j,k;
    fscanf(fin,"%d", &n);
    for(i=n-1; i>0; i--)
    {
        for(j=n; j>0; j--)
            for(k=1; k<=i; k++)
                fprintf(fout,"%d %d\n", j,j+1);
        for(k=1; k<=i; k++)
                fprintf(fout,"%d %d\n", n+1, 1);
    }
    return 0;
}