import java.util.*;

class Flight {
    public String origin;
    public String dest;
    public String op_unique_carrier;
    /* other fields from the real data intentionally omitted */

    public Flight(String origin, String dest, String op_unique_carrier) {
        this.origin = origin;
        this.dest = dest;
        this.op_unique_carrier = op_unique_carrier;
    }
}

class OutputRow {
    public int competition_factor;
    public int count;

    public OutputRow(int competition_factor, int count) {
        this.competition_factor = competition_factor;
        this.count = count;
    }

    @Override
    public String toString() {
        return "(" + competition_factor + ", " + count + ")";
    }
}

public class HW4 {
    public static List<OutputRow> problem2(List<Flight> flights) {
        // TODO: your code here
        return null;
    }

    public static void main(String[] args) {
        List<Flight> mock_flights = new ArrayList<>();
        mock_flights.add(new Flight("SEA", "ORD", "Alaska"));
        mock_flights.add(new Flight("SEA", "ORD", "United"));
        mock_flights.add(new Flight("SEA", "ORD", "Delta"));

        mock_flights.add(new Flight("SEA", "SFO", "Alaska"));
        mock_flights.add(new Flight("SEA", "SFO", "Delta"));

        mock_flights.add(new Flight("SFO", "LAX", "Alaska"));
        mock_flights.add(new Flight("SFO", "LAX", "Delta"));

        mock_flights.add(new Flight("SFO", "ORD", "United"));

        mock_flights.add(new Flight("SEA", "JNU", "Alaska"));

        List<OutputRow> output = problem2(mock_flights);
        for (OutputRow row : output) {
            System.out.println(row);
        }
    }
}

// Expected output:
// 
//     (3, 1)
//     (2, 2)
//     (1, 2)
//
// Your code will be tested on other data, so do not hard code the answer.