import java.util.*;


public class Solution {
    /**
     * 反转字符串
     * @param str string字符串 
     * @return string字符串
     */
    public String solve (String str) {
        // write code here
        StringBuffer sb = new StringBuffer();
        for(int i = str.length() - 1; i >= 0; i--){
            sb.append(str.charAt(i));
        }
        return sb.toString();
    }
}