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

class Meguru
{

    public Meguru() { }
    public static int Main()
    {
        new Meguru().calc();
        return 0;
    }

    Scanner cin;

    //今日は2問目までしか解きませんよ！
    void calc()
    {
        cin = new Scanner();
        int start = -1;
        string S = cin.next();
        List<int> c = new List<int>();
        List<int> w = new List<int>();
        for (int i = 0; i < S.Length; i++)
        {
            if (S[i] == 'c') c.Add(i);
            else if (S[i] == 'w') w.Add(i);
        }
        int ans = int.MaxValue;
        foreach (var c1 in c)
        {
            foreach (var c2 in w)
            {
                foreach (var c3 in w)
                {
                    if (c1 < c2 && c2 < c3)
                    {
                        ans = Math.Min(ans, c3 - c1) + 1;
                    }
                }
            }
        }

        if (ans == int.MaxValue) Console.WriteLine(-1);
        else Console.WriteLine(ans);
    }
}





class Scanner
{
    string[] s;
    int i;

    char[] cs = new char[] { ' ' };

    public Scanner()
    {
        s = new string[0];
        i = 0;
    }

    public string next()
    {
        if (i < s.Length) return s[i++];
        string st = Console.ReadLine();
        while (st == "") st = Console.ReadLine();
        s = st.Split(cs, StringSplitOptions.RemoveEmptyEntries);
        i = 0;
        return next();
    }

    public int nextInt()
    {
        return int.Parse(next());
    }

    public long nextLong()
    {
        return long.Parse(next());
    }

    public double nextDouble()
    {
        return double.Parse(next());
    }

}