Permute Digits

Description:

Input:

The first line contains integer a (1 ≤ a ≤ 10¹⁸). The second line contains integer b (1 ≤ b ≤ 10¹⁸). Numbers don't have leading zeroes. It is guaranteed that answer exists.

Output:

Print the maximum possible number that is a permutation of digits of a and is not greater than b. The answer can't have any leading zeroes. It is guaranteed that the answer exists.

The number in the output should have exactly the same length as number a. It should be a permutation of digits of a.

Sample Input:

123
222

Sample Output:

213

Sample Input:

3921
10000

Sample Output:

9321

Sample Input:

4940
5000

Sample Output:

4940