#include <fstream>
#include <cstdio>

using namespace std;

int N, i;
int 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;
}