import java.util.Scanner;
public class Test99 {
public static void main(String[] args) {
System.out.println("请输入字符串");
Scanner cin = new Scanner(System.in);
while(cin.hasNext()) {
int[] num = new int[26];
String line = cin.nextLine();
for(int i=0; i<line.length(); i++) {
char c = line.charAt(i);
int n = (int)(c - 'a');
num[n] ++;
}
int max = 0;
for(int i=0; i<26; i++) {
if(num[i] != 0 && num[i] > max) {
max = num[i];
}
}
for(int i=0; i<line.length(); i++) {
char c = line.charAt(i);
int n = (int)(c - 'a');
if(num[n] != max) {
System.out.print(c);
}
}
System.out.println();
}
}
}