using System;

namespace yukicoder
{
    class Program
    {
        static void Main(string[] args)
        {
            string s = Console.ReadLine();
            int count = 0;
            int ans = 0;
            int c = 0;
            int w = 0;
            int wcount=0;
            if (s.IndexOf("cww") != -1)
            {
                ans = 3;
            }
            else
            {
                for (int i = 0; i < s.Length; i++)
                {
                    string a = s.Substring(i, 1);
                    count++;
                    if (a == "c" && w == 0)
                    {
                        c = count;
                    }
                    if (c >= 1 && a == "w")
                    {
                        w = count;
                        wcount++;
                        if (wcount == 2)
                        {
                            if (ans == 0)
                            {
                                ans = w - c + 1;
                            }
                            else if (ans > w - c)
                            {
                                ans = w - c ;
                            }

                            c = 0;
                            w = 0;
                            wcount = 0;
                        }
                    }

                }
                if (ans == 0)
                {
                    ans = -1;

                }
            }

            Console.WriteLine(ans);
        }
    }
}