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;

            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;
                        }else if (ans > w - c)
                        {
                            ans = w - c;
                        }
                        
                        c = 0;
                        w = 0;
                        wcount = 0;
                    }
                }

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