/*
http://yukicoder.me/problems/984
*/
using System;

public class ycNo35
{
  public static void Main()
  {
    string str = Console.ReadLine();
    string search_c = "c";
    string search_w = "w";
    int min = -1;
    while(str.Length != 0)
    {
      int cFindIndex = str.IndexOf(search_c);
      if(cFindIndex <= 0) {break;}
      //先頭文字から最初のcまでを削除
      str = str.Remove(0,cFindIndex);
      //以降２つのwを見つける
      //１つ目
      int wFindIndex = str.IndexOf(search_w);
      if(wFindIndex <= 0){break;}
      //２つ目
      wFindIndex += str.IndexOf(search_w,wFindIndex + 1);
      if(min < 0) min = wFindIndex;
      else if(min > wFindIndex) min = wFindIndex;
    }
    Console.Write(min);
  }

}