C# LinkedList Contains Method

using System;
using System.Collections.Generic;

class Demo {
   static void Main() {
      int [] num = {1, 3, 7, 15};
      LinkedList<int> list = new LinkedList<int>(num);                  
      foreach (var n in list) {  
         Console.WriteLine(n);  
      }    
      // adding a node at the end
      var newNode = list.AddLast(20);
      
      // adding a new node after the node added above
      list.AddAfter(newNode, 30); 
      Console.WriteLine("LinkedList after adding new nodes...");
      foreach (var n in list) {  
         Console.WriteLine(n);  
      }   
      Console.WriteLine("Is number 3 (node) in the list?: "+list.Contains(3));
   }
}