import java.util.Arrays;

 public class Solution {

     public int nextGreaterElement(int n) {

         char[] number = (n + "").toCharArray();

         int i, j;

         // I) Start from the right most digit and

         // find the first digit that is

         // smaller than the digit next to it.

         for (i = number.length-1; i > 0; i--)

             if (number[i-1] < number[i])

                 break;

         // If no such digit is found, its the edge case 1.

         if (i == 0)

             return -1;

         // II) Find the smallest digit on right side of (i-1)'th

         // digit that is greater than number[i-1]

         int x = number[i-1], smallest = i;

         for (j = i+1; j < number.length; j++)

             if (number[j] > x && number[j] <= number[smallest])

                 smallest = j;

         // III) Swap the above found smallest digit with

         // number[i-1]

         char temp = number[i-1];

         number[i-1] = number[smallest];

         number[smallest] = temp;

         // IV) Sort the digits after (i-1) in ascending order

         Arrays.sort(number, i, number.length);

         long val = Long.parseLong(new String(number));

         return (val <= Integer.MAX_VALUE) ? (int) val : -1;

     }

 }