using System;

using System.Text;

using System.Collections.Generic;   

using System.Globalization;

public class Program

{

    public static void Main()

    {

        Console.WriteLine(ReplaceDiacritics("Кондиционирование"));

    }

           public static string ReplaceDiacritics(string input)

        {

            var map = new Dictionary<char, string>()

            {

                //*** german

                {'ä', "a"},

                {'ö', "o"},

                {'ü', "u"},

                {'Ä', "A"},

                {'Ö', "O"},

                {'Ü', "U"},

                {'ß', "s"},

                //*** french

                {'é', "e"},

                {'è', "e"},

                {'ë', "e"},

                {'ê', "e"},

                {'ï', "i"},

                {'î', "i"},

                {'ô', "o"},

                {'ç', "c"},

                {'à', "a"},

                {'â', "a"},

                {'ù', "u"},

                {'û', "u"},

                //Added spain special characters

                {'á',"a"},

                {'í',"i" },

                {'ó',"o"},

                {'ú',"u"},

                {'ñ',"n"},

                {'¿' ,"?"},

                {'¡',"!"},

​

                //Added russian special characters

                {'а', "a" },

            {'б', "b"},

            {'в', "v"},

            {'г', "g"},

            {'д', "d"},

            {'е', "e"},

            {'ё', "yo"},

            {'ж', "zh"},

            {'з', "z"},

            {'и', "i"},

            {'й', "j"},

            {'к', "k"},

            {'л', "l"},

            {'м', "m"},

            {'н', "n"},

            {'о', "o"},

            {'п', "p"},

            {'р', "r"},

            {'с', "s"},

            {'т', "t"},

            {'у', "u"},

            {'ф', "f"},

            {'х', "h"},

            {'ц', "c"},

            {'ч', "ch"},

            {'ш', "sh"},

            {'щ', "sch"},

            {'ъ', "j"},

            {'ы', "i"},

            {'ь', "j"},

            {'э', "e"},

            {'ю', "yu"},

            {'я', "ya"},

            {'А', "A"},

            {'Б', "B"},

            {'В', "V"},

            {'Г', "G"},

            {'Д', "D"},

            {'Е', "E"},

            {'Ё', "Yo"},

            {'Ж', "Zh"},

            {'З', "Z"},

            {'И', "I"},

            {'Й', "J"},

            {'К', "K"},

            {'Л', "L"},

            {'М', "M"},

            {'Н', "N"},

            {'О', "O"},

            {'П', "P"},

            {'Р', "R"},

            {'С', "S"},

            {'Т', "T"},

            {'У', "U"},

            {'Ф', "F"},

            {'Х', "H"},

            {'Ц', "C"},

            {'Ч', "Ch"},

            {'Ш', "Sh"},

            {'Щ', "Sch"},

            {'Ъ', "J"},

            {'Ы', "I"},

            {'Ь', "J"},

            {'Э', "E"},

            {'Ю', "Yu"},

            {'Я', "Ya"},

        };

​

            var output = new StringBuilder();

​

            foreach (var item in input)

            {

                output.Append(map.ContainsKey(item) ? map[item].ToString(CultureInfo.InvariantCulture) : item.ToString(CultureInfo.InvariantCulture));

            }

​

            return output.ToString();

        }

}