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);
}
}
}