#include <iostream>
#include <vector>

using namespace std;

int main() {
    long long X;
    cin >> X;

    const int MAX_N = 200000;

    if (X + 1 > MAX_N) {
        cout << -1 << endl;
        return 0;
    }

    int n = X + 1;
    cout << n << endl;

    // Build a star tree with center at vertex 1 (brown), connected to X green vertices
    for (int i = 2; i <= n; ++i) {
        cout << "1 " << i << endl;
    }

    // Output colors: 'b' for vertex 1, 'g' for vertices 2 to n
    cout << "b";
    for (int i = 2; i <= n; ++i) {
        cout << " g";
    }
    cout << endl;

    return 0;
}