#include <cstdio>

using namespace std;

int main(){
    freopen("tije.in", "r", stdin);
    freopen("tije.out", "w", stdout);

    int n;
    scanf(" %d ", &n);
    for (int i= n-1; i>0; --i)
    {
        for (int j= n; j>0; --j)
           for (int k= 1; k<=i; ++k) printf("%d %d\n", j, j+1);
        for (int j= 1; j<=i; ++j) printf("%d 1\n", n+1);
    }
    return 0;
}