using System.Collections.Generic;
using System.Collections;
class X : IEnumerable<(int, int)>
private List<(int, int)> Numbers = new ();
public void Add(int n, int y)
IEnumerator IEnumerable.GetEnumerator() => GetEnumerator();
public IEnumerator<(int, int)> GetEnumerator() => Numbers.GetEnumerator();
public static void Main()
Console.WriteLine("Hello World");