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

public class P0345 {
    public static void Main() {
        var s = Console.ReadLine().Trim().ToCharArray();
        var clist = new List<int>();
        var wlist = new List<int>();
        for(int i=0; i<s.Length; i++) {
            if(s[i] == 'c') clist.Add(i);
            if(s[i] == 'w') wlist.Add(i);
        }
        var result = s.Length + 1;
        for(int i=0; i<clist.Count(); i++) {
            var c = clist[i];
            var wcount = 0;
            for(int j=0; j<wlist.Count(); j++) {
                if(c < wlist[j]) wcount++;
                if(wcount == 2) {
                    result = Math.Min(result, wlist[j] - c + 1);
                    break;
                }
            }
        }
        if(result == s.Length + 1) {
            Console.WriteLine(-1);
        } else {
            Console.WriteLine(result);
        }
    }
}