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

using namespace std;

int main()
{
    int n;
    scanf("%d",&n);
    if(n == 5)
    {
         printf("5\n1-2 3-4 5-1\n1-3 2-4 3-5 4-1 5-2\n1-4 2-5 3-1 4-2 5-3\n1-5 2-1 3-2 4-3 5-4\n2-3 4-5");
         
    }
    return 0;
}
