using System;

using System.Collections.Generic;

using System.Linq;

public class Program

{

    public static void Main()

    {

        var list = new List<int> { 1, 2, 3, 4, 5 };

        var list2 = list.M(x => x*x);

        Console.WriteLine(list2.Last());

    }

}

​

public static class Fun

{

    public static IEnumerable<T> M<T>(this IEnumerable<T> ts, Func<T,T> f)

    {

        return ts.Select(f);

    }

}