import java.util.*;

public class Main{
public static void main(String[] args){
Scanner sc = new Scanner(System.in);
String str = sc.next();
int[] a = new int[10];
for(int i = str.length() - 1; i >= 0; i--){
int c = str.charAt(i) - 48;
if(a[c] == 0){
System.out.print(c);
a[c] = 1;
}
}
}
}