using System;
using System.Collections.Generic;
using System.Linq;
public class MainClass {
public static void Main() {
var numbers = new List() { 1, 2 };
IEnumerable query = numbers.Select(n => n * 10);
foreach (int n in query) Console.Write(n + "|");
numbers.Clear();
foreach (int n in query) Console.Write(n + "|");
}
}