public static string StrInc([NotNull] string s)
        {
            if (s == null) throw new ArgumentNullException(nameof(s));
            var m = Regex.Match(s, @"(?<prefix>[A-Za-z]+)?(?<number>\d+)", RegexOptions.Compiled);
            if (m.Success)
            {
                var prefixGroup = m.Groups["prefix"];
                var prefix = prefixGroup.Success ? prefixGroup.Value : string.Empty;
                var number = m.Groups["number"].Value;
                var n = long.Parse(number);
                return prefix + (++n).ToString().PadLeft(number.Length, '0');
            }
            throw new ArgumentException("Wrong input string!", nameof(s));
        }

        public static string StrInc2([NotNull] string s)
        {
            if (string.IsNullOrEmpty(s)) throw new ArgumentException("Wrong string.", nameof(s));
            var b = new char[s.Length];
            var i = s.Length;
            while (--i >= 0 && char.IsDigit(s[i]))
            {
                var d = s[i] + 1;
                if (d > '9')
                {
                    b[i] = '0';
                }
                else
                {
                    b[i] = (char)d;
                    break;
                }
            }
            while (--i >= 0) b[i] = s[i];
            return new string(b);
        }