세 부분

import java.io.*;
import java.util.*;
class Main{
    public static void main(String[] args) throws IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        String word = br.readLine();
        PriorityQueue<String> pq = new PriorityQueue<>();
        for(int i=1 ; i<word.length();i++){
            for(int j=i+1 ; j< word.length();j++){
                StringBuilder a = new StringBuilder(word.substring(0,i));
                StringBuilder b = new StringBuilder(word.substring(i,j));
                StringBuilder c = new StringBuilder(word.substring(j,word.length()));
                StringBuilder sb = new StringBuilder();
                sb.append(a.reverse())
                .append(b.reverse())
                .append(c.reverse());
                pq.add(sb.toString());
            }
        }
        System.out.print(pq.poll());
    }
}