import java.util.*;
 
public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        String S = sc.next();
        String[] sp = S.split("");
        Deque<String> deque = new ArrayDeque<>();
        for(String s : sp) {
            if(s.equals("0") || s.equals("1")) deque.push(s);
            else {
                if(deque.size() != 0) deque.pop();
            }
        }
        StringBuilder ans = new StringBuilder();
        for(String a : deque) {
            ans.insert(0, a);
        }
        System.out.println(ans);
    }
    
}
/tmp/hf-datasets-cache/medium/datasets/42704881117311-config-parquet-and-info-qiankunmu-Project_CodeNet-896c9d36/hub/datasets--qiankunmu--Project_CodeNet_Python800_and_Java250/snapshots/c899fde44a77ba1cc14973ed3de064e4ff3aadc7/Project_CodeNet_Java250.tar.gz