using System;

using System.Collections.Generic;

using System.Linq;

using System.Text.Json;

​

public class Program

{

    public static void Main()

    {

        //var tupleList = new List<(int, string)>{(1, "cow"), (5, "chickens"), (1, "airplane")};

        var tupleList = new List<List<int>>{new List<int>{1, 3}, new List<int>{2, 4}};

        var tupleListString = String.Join(";", tupleList);

        //Console.WriteLine(tupleListString);

        //  var tupleSplit = tupleListString.Split(';');

        //  Console.WriteLine(tupleSplit[0]);

        //  (int, string) a = tupleSplit[0];

        var json = JsonSerializer.Serialize(tupleList);

        Console.WriteLine(json);

    }

}