题解 | #数字颠倒#

import java.util.*;

public class Main {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        int num = in.nextInt();
        StringBuilder s2 = new StringBuilder();

        String s1 = Integer.toString(num);

        for (int i = s1.length()-1; i >= 0; --i) {
            s2.append(s1.charAt((i)));
        }

        System.out.println(s2);
    }
}