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
            {
                start = s.IndexOf("c");
                if (start != -1)
                {
                    w = s.IndexOf("w", start);
                }
                if (w != -1)
                {
                    end = s.IndexOf("w", w + 1);
                }
                
                if(end!=-1)
                ans=end-start+1;
            }
            if (ans == 0)
            {
                ans = -1;
            }
            Console.WriteLine(ans);
        }
    }
}