#include <iostream>
using namespace std;
int main(){
    int k;
    int m[10][10];
    cin >> k;
    cout << 6 << endl;
    cout << 0 << " " << 0 << endl;
    cout << 0 << " " << 1 << endl;
    cout << 0 << " " << 2 << endl;
    cout << 1 << " " << 1 << endl;
    cout << 1 << " " << 2 << endl;
    cout << 1 << " " << 3 << endl;
}