题解 | #字符逆序#

import java.util.Scanner;

// 注意类名必须为 Main, 不要有任何 package xxx 信息
public class Main {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        
        String str = in.nextLine();

        StringBuilder re = new StringBuilder();
        // StringBuilder re = new StringBuilder(str);
        // System.out.println(re.reverse());

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

        System.out.println(re);
    }
}