#define _CRT_SECURE_NO_WARNINGS
#define _SILENCE_CXX17_C_HEADER_DEPRECATION_WARNING
#include <bits/stdc++.h>
using namespace std;
int main()
{
    int n;
    scanf("%d", &n);
    printf("%d %d\n", n - 1, n);
    for (int i = 0; i < n; i++)
        printf("%d %d\n", (i % n) + 1, ((i + 1) % n) + 1);
    return 0;
}