using System.Collections.Generic;
static void Main(string[] args)
var stays = new List<Stay>() {
new Stay("2019-11-16 2019-11-19"),
new Stay("2019-11-18 2019-11-20"),
new Stay("2019-11-19 2019-11-22")
var mostPopularDay = FindMostPopularDay(stays);
Console.WriteLine(mostPopularDay.ToString("yyyy-MM-dd"));
private static DateTime FindMostPopularDay(IList<Stay> stays)
public Stay(string startAndEndDates)