import java.util.HashSet; import java.util.Scanner;

public class Main { public static void main(String[] args) { Scanner scanner = new Scanner(System.in); String str = scanner.nextLine(); scanner.close(); HashSet hs = new HashSet<>();

    //write your code here......
    for(int i = 0;i<str.length();i++){
        hs.add(str.charAt(i));
    }
    for (char c:hs) {
        System.out.print(c);
    }
}

}