using System;
namespace yukicoder
{
    class Program
    {

        static void Main(string[] args)
        {

            var str = Console.ReadLine();
            string[] strings = new string[str.Length];
            int C = 0 , W = 0 ,  Ccnt = 0 , Wcnt = 0 , anscount = 0;


            for (int i = 0; i < str.Length; i++)
            {
                if(str.Substring(i,1) == "c" && Wcnt == 0)
                {        
                    C = 1;
                    Ccnt = i;
                }
                else if (str.Substring(i, 1) == "w" && C == 1)
                {
                    W++;
                    Wcnt = i;
                }
                
                if(C == 1 && W == 2)
                {
                    int sum = Wcnt - Ccnt + 1;
                    anscount = sum;
                    C = 0;
                    Ccnt = 0;
                    W = 0;
                    Wcnt = 0;
                }
                
            }

            if(anscount > 0)
            {
                Console.WriteLine(anscount);
            }
            else if (anscount == 0)
            {
                Console.WriteLine("-1");
            }
        }
    }
}