#include <iostream>
#include <cmath>
using namespace std;
void ft_hanoi(int a, int b, int n)
{
int c;
if (n == 1)
{
cout << a << ' ' << b << '\n';
return ;
}
c = 6 - a - b;
ft_hanoi(a, c, n - 1);
cout << a << ' ' << b << '\n';
ft_hanoi(c, b, n - 1);
}
int main()
{
ios::sync_with_stdio(0);
cin.tie(0);
int n;
int count;
cin >> n;
count = pow(2, n) - 1;
cout << count << '\n';
ft_hanoi(1, 3, n);
return (0);
}