using System.Collections.Generic;
public static void Main()
var list = new List<int>(){1,5,7,3,19};
var index = list.FindIndex(x=>x == 5);
Console.WriteLine(index);
Func<int, int> func1 = x => x + 1;
Console.WriteLine(func1.Invoke(6));
Func<int, int, int> multiply = (x,y) => x * y;
Console.WriteLine(multiply.Invoke(4,5));