using System;
using System.Collections.Generic;
using System.Linq;

namespace chiwawa
{
    class Program
    {
        static void Main(string[] args)
        {
            var input = Console.ReadLine();

            var len = input.Length;

            var chiwawaList = new List<Chiwawa>();

            for (int i = 0; i < len; i++)
            {
                if(input[i] == 'c')
                {
                    chiwawaList.Add(new Chiwawa(i));
                }
                else if(input[i] == 'w')
                {
                    chiwawaList.ForEach(x => x.FindW(i));
                }
            }

            var min = (chiwawaList.Any()) ? chiwawaList.Min(x => x.Length()) : 101;

            Console.WriteLine(min == 101 ? -1 : min);
        }
    }

    public class Chiwawa
    {
        private int _first;
        private int _end;
        private bool _nextIsEnd;
        private bool _isEnd;

        public Chiwawa(int CIndex)
        {
            _first = CIndex;
        }

        public void FindW(int WIndex)
        {
            if (_nextIsEnd && _isEnd == false)
            {
                _end = WIndex;
                _isEnd = true;
            }
            else
            {
                _nextIsEnd = true;
            }
        }

        public int Length()
        {
            if(_isEnd) { return _end - _first + 1; }

            return 101;
        }
    }
}