Pluralize rubles C#

PluralizeTask.cs

using System;

namespace Pluralize
{
    public static class PluralizeTask
    {
        public static string PluralizeRubles(int count)
        {
            if (count % 10 == 1 && count % 100 != 11)
                return "рубль";
            if (Array.IndexOf(new[] { 2, 3, 4 }, count % 10) != -1 &&
                Array.IndexOf(new[] { 12, 13, 14 }, count % 100) == -1)
                return "рубля";
            return "рублей";
        }
    }
}