using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Text.RegularExpressions;
using System.Threading.Tasks;

namespace ConsoleApp1
{
    class Program
    {
        private const string CWW = "c.*?w.*?w";

        static void Main(string[] args)
        {
            var target = Console.ReadLine();
            var r = Regex.Matches(target, CWW);

            if (r == null)
            {
                Console.WriteLine("-1");
                return;
            }
            var min = 101;

            GetMinValue(r, ref min);

            // 逆方向からの検索
            r = Regex.Matches(target, CWW, RegexOptions.RightToLeft);

            GetMinValue(r, ref min);

            Console.WriteLine(min);
        }

        private static void GetMinValue(MatchCollection target, ref int min)
        {
            foreach (Match match in target)
            {
                if (min > match.Length)
                {
                    min = match.MatcheEx(CWW).Value.Length;
                }
            }
        }
    }

    public static class MatchEX
    {
        public static Match MatcheEx(this Match match, string pat)
        {
            var target = match.Value.Substring(1);
            var search = Regex.Matches(target, pat);

            if(search.Count == 0)
            {
                return match;
            }
            else if (search.Count == 1)
            {
                return search[0].MatcheEx(pat);
            }
            else
            {
                throw new Exception("too match");
            }
        }
    }
}