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 cnum = input.IndexOf("c", 0);
            int wcnt = 0;
            int length = -1;
            for(int i=cnum;i<input.Length;i++)
            {
                string temp = input.Substring(i, 1);
                if(temp=="w")
                {
                    wcnt++;
                    if(wcnt==2)
                    {
                        length = i+1;
                        break;
                    }
                }
            }
            if (length != -1)
            {
                Console.WriteLine(length - cnum);
            }
            else
            {
                Console.WriteLine("-1");
            }
        }

    }
}