Nahid has his own printing press, “Desher Khobor” . He feels that words on their own simply aren't beautiful enough. So, he wishes to make a Super machine. Now what does this machine do?
The machine aims to make words as beautiful as they can be by making a word as lexicographically small as possible. Nahid, being the resourceful person he is, has a reserve string from which we can choose characters that will replace characters in the original word that machine wishes to transform.
Keep in mind that once you have used a letter in the reserve string, it is removed from the reserve.
As Nahid is busy with other works, it's your task to take care of programming the machine .
Note that you cannot modify the original order of the letters in the word that has to be transformed. You can only replace its letters with those in the reserve.
The first line of input contains T. T test cases follow.
Each test case has 2 lines.
The first line of each test case has the word W, that has to be transformed.
The second line of each test case has a reserve R from which we will pick letters.
The output should contain T lines with the answer to each test on a new line.
Print a word P which is the lexicographically smallest that can be obtained on replacing letters of W with letters from R.
3 bbbb aaa zxewya abcd ac zzzb
aaab abcdya ab
In the first test case, we have 3 a' s , so we simply replace the first 3 letters of the word.