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

public class YukiCoder
{
    public static void Solve()
    {
	    var S = MyConsole.String();
	    
	    var fnc = new Func<int>( () => {

	        int cIdx = -1;
	        int wIdx = 0;
	        int min = 101;

	        while (true)
	        {
	            cIdx = S.IndexOf( 'c', cIdx + 1 ); if (cIdx < 0) break;
	            wIdx = S.IndexOf( 'w', cIdx + 1 ); if (wIdx < 0) break;
	            wIdx = S.IndexOf( 'w', wIdx + 1 ); if (wIdx < 0) break;

	            min = Math.Min( min, wIdx - cIdx + 1 );
	        }

	        return min == 101 ? -1 : min;
	    } );

	    MyConsole.wLine( fnc().ToString() );
    }

    public static void Main()
    {
        MyConsole.Read(); Solve(); MyConsole.Finish();
    }
}

public static class MyConsole
{
    private static List<string> ReadedLine = new List<string>();
    private static char[] buf = new char[1024];
    private static int i;

    public static void Read()
    {
        string sr = Console.In.ReadToEnd();

        ReadedLine = sr.Split( new[] { '\r', '\n' }, StringSplitOptions.RemoveEmptyEntries ).ToList();

        InputRowCnt = ReadedLine.Count;

        Console.SetOut( new StreamWriter( Console.OpenStandardOutput() ) { AutoFlush = false } );
    }

    public static int InputRowCnt = 0;

    public static string String() { return ( i + 1 > ReadedLine.Count ) ? "" : ReadedLine[i++]; }
    public static string[] StringSplit() { return ReadedLine[i++].Split( new[] { ' ' } ); }

    public static int Int() { return int.Parse( ReadedLine[i++] ); }
    public static int[] IntSplit()
    {
        string[] strs = StringSplit();
        int[] ret = new int[strs.Length];
        for (int i = 0 ; i < strs.Length ; i++)
        {
            ret[i] = int.Parse( strs[i] );
        }

        return ret;
    }
    public static long Long() { return long.Parse( ReadedLine[i++] ); }
    public static double Double() { return double.Parse( ReadedLine[i++] ); }

    public static void Write( string output = null )
    {
        Console.Write( output );
    }

    public static void wLine( string output = null )
    {
        Console.WriteLine( output );
    }

    public static void Finish()
    {
        Console.Out.Flush();
    }
}