#include <iostream>
#include <fstream>
#include <vector>
using namespace std;
ifstream in("tije.in");
ofstream out("tije.out");
vector <pair <int, int> > sol;
string s;

void add(int x)
{
    string aux;
    while(x > 0)
    {
        aux += (char)(x % 10 + '0');
        x = x / 10;
    }
    s += aux;
}

int main()
{
    int n;
    in >> n;
    int last = n + 1;
    n--;
    for(int i = n; i >= 1; i--)
    {
        for(int j = n + 1; j >= 1; j--)
            for(int k = 1; k <= i; k++)
                sol.push_back(make_pair(j, j + 1));
        for(int j = 1; j <= i; j++)
            sol.push_back(make_pair(last, 1));
    }
    for(auto it : sol)
    {
        add(it.first);
        s += " ";
        add(it.second);
        s += "\n";
    }
    out << s;
    return 0;
}