#include <stdio.h>

long n;

int main()
{
    freopen("tije.in", "rt", stdin);
    freopen("tije.out", "wt", stdout);

    scanf("%ld", &n);

    for(long i = n - 1; i >= 1; --i)
    {
        for(long j = n; j >= 1; --j)
            for(long l = i; l >= 1; --l)
                printf("%ld %ld\n", j, j + 1);

        for(long l = i; l >= 1; --l)
            printf("%ld %ld\n", n + 1, 1);
    }
}