import java.util.Scanner; public class Main{ public static void main(String[] args){ Scanner sc = new Scanner(System.in); String str = sc.nextLine(); int[] temp = new int[26]; char[] chars = str.toCharArray(); for(int i = 0; i < chars.length;i++){ //统计各字母出现的次数 int index = chars[i] - 97; temp[index] += 1;

    }
     //对出现的次数进行排序
    int min = Integer.MAX_VALUE;
    for(int i=0; i < 26; i++){
        if(temp[i] != 0){
            min = Math.min(min,temp[i]);
        }
    }
        //删除出现次数最少的字母
    //如果有相同次数的字母,则一起删除
    for(int i =0; i<26;i++){
        if(temp[i] == min){
            char ch = (char)('a' + i);
            str = str.replace(ch + "","");
        }
    }
      System.out.println(str);  
}

}