using System;

using System.Linq;

using System.Collections.Generic;

public class Program

{

    public static void Main()

    {

        foreach (var item in Zip("Rafael", "Ra"))

            Console.WriteLine(item);

    }

    public static IEnumerable<(T1, T2)> Zip<T1, T2>(IEnumerable<T1> iterable1, IEnumerable<T2> iterable2)

    {       

        IEnumerator<T1> Enumerator1 = iterable1.GetEnumerator();

        IEnumerator<T2> Enumerator2 = iterable2.GetEnumerator();

        //while (Enumerator1.MoveNext() && Enumerator2.MoveNext())

        //{

        //  yield return (Enumerator1.Current, Enumerator2.Current);

        //}

        while (true)

        {

            bool moveNext1 = Enumerator1.MoveNext();

            bool moveNext2 = Enumerator2.MoveNext();

            if (!moveNext1 && !moveNext2)

                break;

            T1 output1 = moveNext1 ? Enumerator1.Current : default(T1);

            T2 output2 = moveNext2 ? Enumerator2.Current : default(T2);

            yield return (output1, output2);

        }

    }

}