Regular Expressions C#

using System;
using System.Collections.Generic;
using System.Text;
using System.Text.RegularExpressions;
public class MainClass{
        public static long CountLinesInStringSlow(string text)
        {
            Regex reg = new Regex("\n", RegexOptions.Multiline);
            MatchCollection mat = reg.Matches(text);
            return mat.Count + 1;
        }
}