import java.io.OutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.Scanner;

/**
 * Built using CHelper plug-in
 * Actual solution is at the top
 */
public class Main {
    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        Scanner in = new Scanner(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        B solver = new B();
        solver.solve(1, in, out);
        out.close();
    }

    static class B {
        public void solve(int testNumber, Scanner in, PrintWriter out) {
            // 入力
            String s = in.next();
            String ans = "";

            for (int i = 0; i < s.length(); i++) {
                char tmp = s.charAt(i);
                if (tmp == '0' || tmp == '1') {
                    ans += s.charAt(i);
                } else {
                    if (ans.length() > 0) ans = ans.substring(0, ans.length() - 1);
                }
            }

            out.println(ans);

        }

    }
}
 import java.io.OutputStream; OutputStream java.io import java.io.IOException; IOException java.io import java.io.InputStream; InputStream java.io import java.io.PrintWriter; PrintWriter java.io import java.util.Scanner; Scanner java.util public class Main {
    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        Scanner in = new Scanner(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        B solver = new B();
        solver.solve(1, in, out);
        out.close();
    }

    static class B {
        public void solve(int testNumber, Scanner in, PrintWriter out) {
            // 入力
            String s = in.next();
            String ans = "";

            for (int i = 0; i < s.length(); i++) {
                char tmp = s.charAt(i);
                if (tmp == '0' || tmp == '1') {
                    ans += s.charAt(i);
                } else {
                    if (ans.length() > 0) ans = ans.substring(0, ans.length() - 1);
                }
            }

            out.println(ans);

        }

    }
} Main public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        Scanner in = new Scanner(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        B solver = new B();
        solver.solve(1, in, out);
        out.close();
    } main {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        Scanner in = new Scanner(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        B solver = new B();
        solver.solve(1, in, out);
        out.close();
    } InputStream inputStream = System.in; inputStream System.in System System.in OutputStream outputStream = System.out; outputStream System.out System System.out Scanner in = new Scanner(inputStream); in new Scanner(inputStream) PrintWriter out = new PrintWriter(outputStream); out new PrintWriter(outputStream) B solver = new B(); solver new B() solver.solve(1, in, out) solver.solve solver 1 in out out.close() out.close out String[] args args static class B {
        public void solve(int testNumber, Scanner in, PrintWriter out) {
            // 入力
            String s = in.next();
            String ans = "";

            for (int i = 0; i < s.length(); i++) {
                char tmp = s.charAt(i);
                if (tmp == '0' || tmp == '1') {
                    ans += s.charAt(i);
                } else {
                    if (ans.length() > 0) ans = ans.substring(0, ans.length() - 1);
                }
            }

            out.println(ans);

        }

    } B public void solve(int testNumber, Scanner in, PrintWriter out) {
            // 入力
            String s = in.next();
            String ans = "";

            for (int i = 0; i < s.length(); i++) {
                char tmp = s.charAt(i);
                if (tmp == '0' || tmp == '1') {
                    ans += s.charAt(i);
                } else {
                    if (ans.length() > 0) ans = ans.substring(0, ans.length() - 1);
                }
            }

            out.println(ans);

        } solve {
            // 入力
            String s = in.next();
            String ans = "";

            for (int i = 0; i < s.length(); i++) {
                char tmp = s.charAt(i);
                if (tmp == '0' || tmp == '1') {
                    ans += s.charAt(i);
                } else {
                    if (ans.length() > 0) ans = ans.substring(0, ans.length() - 1);
                }
            }

            out.println(ans);

        } String s = in.next(); s in.next() in.next in String ans = ""; ans "" for (int i = 0; i < s.length(); i++) {
                char tmp = s.charAt(i);
                if (tmp == '0' || tmp == '1') {
                    ans += s.charAt(i);
                } else {
                    if (ans.length() > 0) ans = ans.substring(0, ans.length() - 1);
                }
            } int i = 0; int i = 0; i 0 i < s.length() i s.length() s.length s i++ i++ i {
                char tmp = s.charAt(i);
                if (tmp == '0' || tmp == '1') {
                    ans += s.charAt(i);
                } else {
                    if (ans.length() > 0) ans = ans.substring(0, ans.length() - 1);
                }
            } {
                char tmp = s.charAt(i);
                if (tmp == '0' || tmp == '1') {
                    ans += s.charAt(i);
                } else {
                    if (ans.length() > 0) ans = ans.substring(0, ans.length() - 1);
                }
            } char tmp = s.charAt(i); tmp s.charAt(i) s.charAt s i if (tmp == '0' || tmp == '1') {
                    ans += s.charAt(i);
                } else {
                    if (ans.length() > 0) ans = ans.substring(0, ans.length() - 1);
                } tmp == '0' || tmp == '1' tmp == '0' tmp '0' tmp == '1' tmp '1' {
                    ans += s.charAt(i);
                } ans += s.charAt(i) ans s.charAt(i) s.charAt s i {
                    if (ans.length() > 0) ans = ans.substring(0, ans.length() - 1);
                } if (ans.length() > 0) ans = ans.substring(0, ans.length() - 1); ans.length() > 0 ans.length() ans.length ans 0 ans = ans.substring(0, ans.length() - 1) ans ans.substring(0, ans.length() - 1) ans.substring ans 0 ans.length() - 1 ans.length() ans.length ans 1 out.println(ans) out.println out ans int testNumber testNumber Scanner in in PrintWriter out out public class Main {
    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        Scanner in = new Scanner(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        B solver = new B();
        solver.solve(1, in, out);
        out.close();
    }

    static class B {
        public void solve(int testNumber, Scanner in, PrintWriter out) {
            // 入力
            String s = in.next();
            String ans = "";

            for (int i = 0; i < s.length(); i++) {
                char tmp = s.charAt(i);
                if (tmp == '0' || tmp == '1') {
                    ans += s.charAt(i);
                } else {
                    if (ans.length() > 0) ans = ans.substring(0, ans.length() - 1);
                }
            }

            out.println(ans);

        }

    }
} public class Main {
    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        Scanner in = new Scanner(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        B solver = new B();
        solver.solve(1, in, out);
        out.close();
    }

    static class B {
        public void solve(int testNumber, Scanner in, PrintWriter out) {
            // 入力
            String s = in.next();
            String ans = "";

            for (int i = 0; i < s.length(); i++) {
                char tmp = s.charAt(i);
                if (tmp == '0' || tmp == '1') {
                    ans += s.charAt(i);
                } else {
                    if (ans.length() > 0) ans = ans.substring(0, ans.length() - 1);
                }
            }

            out.println(ans);

        }

    }
} Main
import java.io.OutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.Scanner;

/**
 * Built using CHelper plug-in
 * Actual solution is at the top
 */
public class Main {
    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        Scanner in = new Scanner(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        B solver = new B();
        solver.solve(1, in, out);
        out.close();
    }

    static class B {
        public void solve(int testNumber, Scanner in, PrintWriter out) {
            // 入力
            String s = in.next();
            String ans = "";

            for (int i = 0; i < s.length(); i++) {
                char tmp = s.charAt(i);
                if (tmp == '0' || tmp == '1') {
                    ans += s.charAt(i);
                } else {
                    if (ans.length() > 0) ans = ans.substring(0, ans.length() - 1);
                }
            }

            out.println(ans);

        }

    }
}

