import java.util.Scanner;
class Main {
  public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    String S = sc.next();
    int c = S.indexOf("c");
    if (c >= 0) {
      int w1 = S.indexOf("w", c + 1);
      if (w1 >= 0) {
        int w2 = S.indexOf("w", w1 + 1);
        if (w2 >= 0) {
          System.out.println(w2 - c +1);
          return;
        }
      }
    } 

    System.out.println(-1);
  }
}