using System;
using System.Text.RegularExpressions;

class No345{
    static void Main(){
        var s=Console.ReadLine();
        var a=new Regex(@"c.*w.*w");
        var r=a.Matches(s);
        var i=101;
        foreach(Match c in r){
        if(i>c.Length)i=c.Length;
        }
        Console.WriteLine(i==101?-1:i);
    }
}