static void Main(string[] args)
{
var distances = new BiDictionary<string, string, int>();
distances.Add("Sofia", "Varna", 443);
distances.Add("Sofia", "Varna", 468);
distances.Add("Sofia", "Varna", 490);
distances.Add("Sofia", "Plovdiv", 145);
distances.Add("Sofia", "Bourgas", 383);
distances.Add("Plovdiv", "Bourgas", 253);
distances.Add("Plovdiv", "Bourgas", 292);
distances.Add("Varna", "Bourgas", 292);
var distancesFromSofia = distances.FindByFirstKey("Sofia"); // [443, 468, 490, 145, 383]
var distancesToBourgas = distances.FindBySecoundKey("Bourgas"); // [383, 253, 292]
var distancesPlovdivBourgas = distances.FindByBothKeys("Plovdiv", "Bourgas"); // [253, 292]
var distancesRousseVarna = distances.FindByBothKeys("Rousse", "Varna"); // []
var distancesSofiaVarna = distances.FindByBothKeys("Sofia", "Varna"); // [443, 468, 490]
distances.Remove("Sofia", "Varna"); // true
var distancesFromSofiaAgain = distances.FindByFirstKey("Sofia"); // [145, 383]
var distancesToVarna = distances.FindBySecoundKey("Varna"); // []
var distancesToVarn1a = distances.FindByFirstKey("Varna"); // []
var distancesSofiaVarnaAgain = distances.FindByBothKeys("Sofia", "Varna"); // []
}
