String generation

Given a string S$1$ of length L$1$ consisting of Latin uppercase alphabets only and a string S$2$ of length L$2$ consisting of characters 'T'and $\text{'}$F$\text{'}$ only.

Generate a lexicographically smallest string S of length $($L$1+$ L$2-1)$ such that a substring of length L$1$ in string S starting at index i $(0<=$ i $<$ L$2)$ is equal to S$1$ if and only if ith element of $$2$ is $\text{'}$T $($without quotes$)$ else not.

If no such string can be generated, print $"-1"($without quotes$).$

Notes

A string a is lexicographically smaller than a string b if and only if one of the following holds:

$$a is a prefix of b$,$ but a $$ b;

$$in the first position where a and b differ, the string a has a letter that appears earlier in the alphabet than the corresponding letter in b$.$

Find the lexicographically smallest string S which satisfies the given condition.

Function description

Complete the solve function. This function takes the following $2$ parameters and returns the answer.

$$S$1$: Represents a string ST

$$S$2$: Represents a string S$2$

Input format for custom testing

Note: Use this input format if you are testing against custom input or writing

$34\backslash$deg C

Mostly cloudy

Search

New Sub

re

$1$

$2$

$3$

$4$

$5$

$7$

$8$

$9$

$10$ V

$11$

$12$

$13$

$14$

$15$

$16$

$17$

code in a language where we don't provide boilerplate code.

$$The first line contains T$,$ which represents the number of test cases.

$$For each test case:

$$The first line contains a string S$1.$

$$The second line contains a string S$2.$

Output format

For each test case, print a string S in a new line or $-1$ if not possible.

Constraints

$1<=$ T $<=102$

$1<=$IS$11<=103$

$1<=|$S$2<=103$

Sample input E

$1$

ABCA

TFFF

Sample output

ABCAAAA