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

public class Test
{
	public static void Main()
	{
    	var s = "123-234;FOO-456;45-67;FOO-FOO;890;FOO-123;11-22;123;123;44-55;098-567;890;123-FOO;";
    	var rx = new Regex(@"(?<=^|;)((?<range>\d+-\d+)|(?<integer>\d+))(?=$|;)", RegexOptions.ExplicitCapture);
    	var result = rx.Matches(s)
    			.Cast<Match>()
    			.Select(x => x.Groups["range"].Success ? 
    				x.Groups["range"].Value : x.Groups["integer"].Value
    			).ToList();
        foreach (var x in result)
        	Console.WriteLine(x);
	}
}