using System;
using System.Text;
using System.Linq;
using System.Collections.Generic;
        
public class Program
{
 
public static void Main(string[] args)
{
    string[] values = { "1", "2", "3a","4" };
    int i = int.MinValue;
    List<int> output = values.Where(s => int.TryParse(s, out i))
                             .Select(s => i)
                             .ToList();
    
    foreach(int num in output)
        Console.WriteLine("Number found: " + num);
}
}