import java.io.BufferedReader;
import java.io.InputStreamReader;

class Main {
  public static void main(String[] args) throws Exception{
    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
      char[] cl = br.readLine().toCharArray();
      StringBuffer sb = new StringBuffer("");
      for (char c : cl){
        if (c == '0' || c == '1' ) {
          sb.append(c);
        } else {
          if(!sb.toString().isEmpty()){
            sb.delete(sb.toString().length() - 1,sb.toString().length());
          }
        }
      }
      System.out.println(sb.toString());
  }
}
/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