using System;
namespace yukicoder
{
    class Program
    {

        static void Main(string[] args)
        {

            var str = Console.ReadLine();
            string[] strings = new string[str.Length];
            int C = 0 , W = 0 ,  Ccnt = str.Length -3 , cc = 0 , Wcnt = 0 , anscount = 0 , temp = str.Length;


            for (int i = 0; i < str.Length; i++)
            {
                if(str.Substring(i,1) == "c" && C == 0)
                {        
                    C = 1;
                    Ccnt = i;
                    
                }
                else if (str.Substring(i, 1) == "c" && C == 1 && cc == 0)
                {
                    cc = i;
                }
                else if (str.Substring(i, 1) == "w" && C == 1)
                {
                    W++;
                    Wcnt = i;
                }
                
                if(C == 1 && W == 2 && Wcnt - Ccnt + 1 > anscount || C == 1 && W == 2 && Wcnt - Ccnt + 1 < anscount )//&& i == str.Length - 1
                {
                    if(anscount == 0)
                    {
                        int sum = Wcnt - Ccnt + 1;
                        anscount = sum;
                        i = cc - 1;
                        C = 0;
                        Ccnt = 0;
                        cc = 0;
                        W = 0;
                        Wcnt = 0;
                    }
                    else
                    {
                        int sum2 = Wcnt - Ccnt + 1;
                        if(temp > sum2)
                        {
                            temp = sum2;
                        }
                        i = cc - 1;
                        C = 0;
                        Ccnt = 0;
                        W = 0;
                        Wcnt = 0;
                        cc = 0;
                    }
                    
                }
                
            }

            if(anscount == 0)
            {
                Console.WriteLine("-1");
            }
            else if (anscount > temp)
            {
                Console.WriteLine(temp);
            }
            else if (anscount < temp)
            {
                Console.WriteLine(anscount);
            }
        }
    }
}