using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Regular
{
    class Program
    {

        static int secondtry(string first)
        {
            int i = 0;
            goto GroupFirst;
            return -2;

        GroupFirst:
            if ((first[i] == 'a') & (i < first.Length - 1))
            {
                i++;
            Brepeat:
                if ((first[i] == 'b') & (i < first.Length - 1))
                {
                    i++;
                    goto Brepeat;
                }
                else if ((first[i] == 'c') & (i < first.Length - 1))
                {
                    i++;
                    if ((first[i] == 'a') & (i < first.Length - 1))
                        goto GroupFirst;
                }
                if ((first[i] == 'd') & (i < first.Length - 1))
                {
                    i++;
                Bplus:
                    if ((first[i] == 'b') & (i < first.Length - 1))
                    {
                        i++;
                        goto Bplus;
                    }
                    else if (first[i + 1] == 'b')
                    {
                        return -1;
                    }
                    else
                        return i + 1;
                }
                else
                    return i;
            }
            else
                return i;
        }

        //(ab*c)+db+
        static int myregular(string first)
        {
            if(first.Length == 0)
            {
                return -2;
            }
            int i = 0;
            bool flag = false;
            Group:
                if ((first[i] == 'a' | !flag) & (i < first.Length - 1))
                {
                    i++;
                    MultiB:
                    if(first[i] == 'b' & (i < first.Length - 1))
                    {
                        i++;
                        goto MultiB;
                    }
                    else if(first[i] == 'c' & (i < first.Length - 1))
                    {
                        i++;
                        flag = true;
                        goto Group;
                    }
                    else
                    {
                        return i;
                    }
                }
                else if(first[i] == 'd' & (i < first.Length - 1))
                {
                    i++;
                    EndB:
                    if (first[i] == 'b' & (i < first.Length - 1))
                    {
                        i++;
                        goto EndB;
                    }
                    else
                    {
                        if (first[i] == 'b')
                            return -1;
                        else
                            return i;
                    }
                }
                else
                {
                    if (first[i] == 'b')
                        return -1;
                    else
                        return i;
                }
        }


        static void Main(string[] args)
        {
            string test = "abbccccc";
            Console.WriteLine(test);
            int number = secondtry(test);
            if (number == -1)
                Console.WriteLine("success");
            else if (number == -2)
                Console.WriteLine("Wrong line");
            else
            {
                number++;
                Console.WriteLine("Unsucces in " + number + " symbol.");
            }
            Console.Read();
        }
    }
}