15 I

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Text.RegularExpressions;
using System.IO;

namespace ConsoleApp1
{


    class Program
    {
        static void Main()
        {
            using (StreamReader input = new StreamReader("d:/input.txt"))
            {
                using (StreamWriter output = new StreamWriter("d:/output.txt", false))
                {

                    var a = input.ReadLine().Split();
                    var ans =   from u in a
                                where u.Length == 2 && int.Parse(u) > 0
                                select u;
                    foreach (var v in ans)
                        output.Write("-" + v + " ");
                }
            }
        }
    }
}