import java.util.*;
public class Main {

	public static void main(String[] args) {
		// TODO 自動生成されたメソッド・スタブ
		Scanner sc = new Scanner(System.in);
		String s = sc.next();
		String ans = "";
		for(int i=0;i<s.length();i++) {
			if(s.charAt(i)=='0' || s.charAt(i)=='1') {
				ans += s.charAt(i);
			}else {
				if(ans.length()!=0) {
					ans = ans.substring(0,ans.length()-1);
				}
			}
		}
		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