using System;

namespace yukicoder
{
    class Program
    {
        static void Main(string[] args)
        {
            string s = Console.ReadLine();
            int start = 0;
            int w=0;
            int end = 0;
            int ans = 0;

            if( s.IndexOf("cww") != -1)
            {
                ans = 3;
            }
            else
            {
                for(int i = 0; i < s.Length-1; i++)
                {
                    start = s.IndexOf("c",i);
                    if (start != -1)
                    {
                        w = s.IndexOf("w", start);
                    }
                    if (w != -1)
                    {
                        end = s.IndexOf("w", w + 1);
                    }
                    else
                    {
                        break;
                    }

                    if (end != -1)
                    {
                        ans = end - start+1;
                    }
                        
                }
       
            }
            if (ans == 0)
            {
                ans = -1;
            }
            Console.WriteLine(ans);
        }
    }
}