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

namespace yukicoderTest
{
    class Program
    {
        static void Main(string[] args)
        {
            string input = Console.ReadLine();
            int len = 0;
            int minlen = 100;
            bool fw = true;
            for (int i = 0; i < input.Length - 1; i++)
            {
                string c = input.Substring(i, 1);
                if (c == "c")
                {
                    len++;
                    fw = true;
                }
                else
                {
                    continue;
                }
                for (int j = i + 1; j < input.Length; j++)
                {
                    string w = input.Substring(j, 1);
                    if (w == "w" && fw == true)
                    {
                        fw = false;

                    }
                    else if (w == "w" && fw == false)
                    {
                        len++;
                        if (minlen > len)
                        {
                            minlen = len;
                        }
                        len = 0;
                        break;
                    }
                    len++;
                }


            }
            if (minlen != 100)
            {
                Console.WriteLine(minlen);
            }
            else
            {
                Console.WriteLine("-1");
            }
        }

    }
}