import java.util.*;
    
    class Solution {
        /*
         * param number: A 3-digit number.
         * return: Reversed number.
         */
        public int reverseInteger(int number) {
            // write your code here
            if (number > 1000 || number <100){
                return -1;
            }
            String s = Integer.toString(number);
            char[] c = s.toCharArray();
            StringBuilder b = new StringBuilder(c.length);
    
            for (int i = s.length()-1; i >= 0; i--){
                b.append(String.valueOf(c[i]));
            }
    
            int y = Integer.parseInt(b.toString());
            return y;
        }
    
        public static void main(String args[]) {
            Solution p = new Solution();
            int ff= p.reverseInteger(102);
            System.out.println(ff); // 201
        }
    }