BAEKJOON_1213

import java.io.*;
import java.sql.Array;
import java.util.*;

public class Main {

    public static void main(String[] args) throws IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));

        int[] alph = new int[26];

        int mid_idx = 0;
        int odd =0;

        StringBuilder sb = new StringBuilder(br.readLine());
        for(int i=0; i<sb.toString().length(); i++){
            alph[sb.toString().charAt(i)-'A']++;
        }

        for(int i=0; i<26; i++){
            if(alph[i]%2 !=0){
                mid_idx=i;
                odd++; 
            }
        }

        if ((sb.toString().length() % 2 != 0 && odd > 1) || (sb.toString().length() % 2 == 0 && odd > 0)) {
            bw.write("I'm Sorry Hansoo");
        }else{
            sb = new StringBuilder("");
            for(int i=0; i<alph.length; i++){
                for(int j=0; j<alph[i]/2; j++){
                    sb.append((char) (i + 'A'));
                }
            }
            String ans = sb.toString();
            String reverse_ans = sb.reverse().toString();

            if(odd==1){
                ans+=(char)(mid_idx + 'A');
            }


            bw.write(ans+reverse_ans);
        }

        bw.flush();
        bw.close();
    }

}