ПОДНИЗ

You are given two strings $a$ and $b$ made of lowercase Latin letters. Write a program substring that finds the longest string which is both a substring of some permutation of $a$ and a substring of some permutation of $b$.

By a "permutation of a string" we mean a string of the same length that contains the characters of the original string in some order.

By a "substring of a string" we mean a string made of a nonzero number of consecutive characters of the given string.

The standard input contains the two strings, each on a separate line. The maximum length of each string is 1000 characters.

On the single line of the standard output, print the sought string. If more than one string of maximum length satisfies the condition, print the lexicographically smallest one.

The given string is a substring of the permutation uamntu of $a$ and of the permutation ornamntuet of $b$.