/*
TASK:mate
LANG:C++
*/
#include <iostream.h>

using namespace std;

int data[102][102];

int main()
{
    int a;
    cin >> a;
    if (a == 1)
    {
          cout << "1" << "\n";
          cout << "1-1" << "\n";
    }
    else if (a == 2)
    {
          cout << "2" << "\n";
          cout << "1-2" << "\n";
          cout << "2-1" << "\n";
    }
    else if (a == 3)
    {
          cout << "3" << "\n";
          cout << "1-2 2-3" << "\n";
          cout << "2-1 1-3" << "\n";
          cout << "2-3 3-1" << "\n";
    }
    else if (a == 4)
    {
          cout << "4" << "\n";
          cout << "1-2 2-4 4-3" << "\n";
          cout << "3-4 4-2 2-1" << "\n";
          cout << "1-3 3-2 4-1" << "\n";
          cout << "2-3 1-4 3-1" << "\n";
    }
    else if (a == 5)
    {
          cout << "5" << "\n";
          cout << "2-4 5-1 3-2 4-5" << "\n";
          cout << "1-3 4-2 3-5" << "\n";
          cout << "3-1 1-5 2-3 5-4" << "\n";
          cout << "1-2 2-5 3-4 5-3 4-1" << "\n";
          cout << "5-2 4-3 1-4 2-1" << "\n";
    }
    else
    {
        cout << a << "\n";
    }
    return 0;
}
