import java.util.*;

public class Exercise31{
  public static void main (String[] args){

    Scanner sc = new Scanner(System.in);

    String str = sc.next();
    char[] charArray = str.toCharArray();

    int min = charArray.length;
    boolean flag = false;

    for (int a = 0; a < charArray.length; a++){
      if (charArray[a] == 'c'){
        for (int b = a + 1; b < charArray.length; b++){
          if (charArray[b] == 'w'){
            for (int c = b + 1; c < charArray.length; c++){
              if (charArray[c] == 'w'){
                  flag = true;
                  min = Math.min(min, (c + 1) - a);
                }
              }
            }
          }
        }
      }
    if (flag){
      System.out.println(min);
    }else{
      System.out.println(-1);
    }
  }
}