using System.Text.RegularExpressions;
using System.Collections.Generic;
using System;
using System.Linq;

public class Program
{
    public static void Main(string[] args)
    {
        Regex r = new Regex(@"[\d-]+");
        var matches = r.Matches("9000-001 a 9999-999");
        
        foreach (var match in matches.Cast<Match>())
        {
            Console.WriteLine($"Encontrada a seguinte ocorrência: '{match.Value}'");
        }
    }
}