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);
            if(r==null){
                Console.WriteLine("-1");
                return;
            }
        var i=101;
        foreach(Match c in r){
        if(i>c.Length)i=c.Length;
        }
        Console.WriteLine(i);
    }
}