import java.util.Scanner;
import java.util.HashMap;
// 注意类名必须为 Main, 不要有任何 package xxx 信息
public class Main {
public static void main(String[] args) {
Scanner scanner = new Scanner(System.in);
String nextLine = scanner.nextLine();
HashMap<Character, Integer> hashMap = new HashMap<>();
char[] toCharArray = nextLine.toCharArray();
for (char aChar : toCharArray) {
if (hashMap.containsKey(aChar)) {
hashMap.put(aChar, hashMap.get(aChar) + 1);
} else {
hashMap.put(aChar, 1);
}
}
int min = Integer.MAX_VALUE;
for (Integer value : hashMap.values()) {
min = Math.min(min, value);
}
for (char aChar : toCharArray) {
if (hashMap.get(aChar) != min) {
System.out.print(aChar);
}
}
System.out.println();
}
}