using System;

using System.Text.RegularExpressions;

public class Program

{

    public static void Main()

    {       

        Console.WriteLine(Regex.Match("1000 - 1009 ABC1 ABC SOMETHING ELSE", @"^\d+\s*-\s*\d+"));

        Console.WriteLine(Regex.Match("1500-2000 ABC1 ABC SOMETHING ELSE", @"^\d+\s*-\s*\d+"));

        Console.WriteLine(Regex.Match("3295  -  2000 ABC1 ABC SOMETHING ELSE", @"^\d+\s*-\s*\d+"));

    }

}