import java.io.*;
import java.util.*;

public class Main{
	public static void main(String args[]){
    	Scanner in = new Scanner(System.in);
      	char[] s = in.next().toCharArray();
      	char[] output = new char[s.length];
      	int k=0;
		 for(int i = 0;i<s.length;i++){
         	if(s[i]!='B'){
           		output[k++] = s[i]; 
            }
           else{
             if(k>0)
           		k--;
           }
         }
      		for(int i =0;i<k;i++){
            	System.out.print(output[i]);
            }
    }
}
/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