import java.util.Scanner;

// 注意类名必须为 Main, 不要有任何 package xxx 信息
public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        String s = sc.next();

        String a = "while";

        String[] arr = new String[s.length()];

        int count = 0;
        for (int i = 0; i < s.length(); i++) {
            String c = a.substring(i, i + 1);
            arr[i] = c;

            if (!arr[i].equals(s.substring(i, i + 1))) {
                count++;
            }
        }
        System.out.println( count);

    }
}