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

public class Hello
{
    public static void Main()
    {
        var c = new List<int>();
        var w = new List<int>();
        var s = Console.ReadLine().Trim();
        for (int i = 0; i < s.Length; i++)
            if (s[i] == 'c') c.Add(i);
            else if (s[i] == 'w') w.Add(i);
        var ans = new List<int>();
        foreach (var x in c)
        {
            var count = 0;
            foreach (var y in w)
            {
                if (y > x) count++;
                if (count == 2) { ans.Add(y -x + 1); break; }
            }
        }
        Console.WriteLine(ans.Count() == 0? -1:ans.Min());
    }
}