#include <bits/stdc++.h>
#define maxN 102
using namespace std;
int n;
void read()
{
    freopen("tije.in", "r", stdin);
    scanf("%d", &n);
}
void write()
{
    int i, j, k;
    freopen("tije.out", "w", stdout);
    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 (j = 1; j <= i; ++ j)
            printf("%d %d\n", n + 1, 1);
    }
}
int main()
{
    read();
    //solve();
    write();
    return 0;
}