Sherlock

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

namespace Shelock
{
    class Program
    {
        static void Main(string[] args)
        {
            string s;
            s = Console.ReadLine();

            if (FullString(s)=="YES")
            {
                Console.WriteLine("YES");
            }


            else
            {



                int counter = 0;
                int[] array = new int[1000];
                for (int i = 0; i < s.Length; i++)
                {
                    string subString = s.Remove(i, 1);
                    //Console.WriteLine(subString);

                    char[] subCharArray = subString.ToCharArray();
                    string holder = "";

                    for (int j = 0; j < subString.Length; j++)
                    {
                        if (!holder.Contains(subCharArray[j]))
                        {
                            holder = holder + subCharArray[j];
                        }

                    }


                    // Console.WriteLine(subString+" contains "+holder);


                    char[] holderArray = holder.ToCharArray();

                    for (int j = 0; j < holder.Length; j++)
                    {
                        int cntLetter = 0;

                        for (int k = 0; k < subString.Length; k++)
                        {
                            if (holderArray[j] == subCharArray[k])
                            {
                                cntLetter++;
                            }
                        }

                        array[j] = cntLetter;




                        //   Console.WriteLine(holderArray[j]+" is "+cntLetter+" times");


                    }

                    int arrLength = 0;
                    for (int j = 0; j < holder.Length; j++)
                    {
                        arrLength = arrLength + 1;
                        // Console.WriteLine(array[j]+" ");
                    }

                    int maxNumber = array.Max();
                    int minNumber = MinNumber(array, arrLength);

                    //Console.WriteLine("Max Number :"+maxNumber);
                    //Console.WriteLine("Min Number :"+minNumber);


                    if (maxNumber == minNumber)
                    {
                        counter++;

                    }





                }


                if (counter > 0)
                {
                    Console.WriteLine("YES");
                }

                else
                {
                    Console.WriteLine("NO");
                }



            }





















            Console.ReadKey();
        }


        static int  MinNumber(int[] arr, int arrLength )
        {
            int tem;
            for (int i = 0; i < arrLength-1; i++)
            {
                for (int j = i+1; j <arrLength; j++)
                {
                    if (arr[i]>arr[j])
                    {
                        tem = arr[i];
                        arr[i] = arr[j];
                        arr[j] = tem;

                    }

                }


            }

            int[] arr2 = arr;

            return arr[0];

        }


        static string FullString(string s)
        {

            char[] CharArray = s.ToCharArray();
            string holder = "";
            int[] array=new int[1000];
            for (int j = 0; j < s.Length; j++)
            {
                if (!holder.Contains(CharArray[j]))
                {
                    holder = holder + CharArray[j];
                }

            }


            char[] holderArray = holder.ToCharArray();

            for (int j = 0; j < holder.Length; j++)
            {
                int cntLetter = 0;

                for (int k = 0; k < s.Length; k++)
                {
                    if (holderArray[j] == CharArray[k])
                    {
                        cntLetter++;
                    }
                }

                array[j] = cntLetter;




                //   Console.WriteLine(holderArray[j]+" is "+cntLetter+" times");


            }

            int arrLength = 0;
            for (int j = 0; j < holder.Length; j++)
            {
                arrLength = arrLength + 1;
                // Console.WriteLine(array[j]+" ");
            }

            int maxNumber = array.Max();
            int minNumber = MinNumber(array, arrLength);

            string returnString;

            if (maxNumber==minNumber)
            {
                returnString = "YES";

            }

            else
            {
                returnString = "NO";
            }

            return returnString;

        }




    }
}