Merging of two strings is sometimes needed in a Python program. Merge of strings A and B may be defined as concatenation resulting in AB$.$ However, it can have other variations.

One method is unique merge, which checks for any redundancy between end of the first string A and the start of the second string B$,$ and removes it$.$

For example, if the first string is "program" and the second string is "grammar", then their unique merge is "programmar". Other examples are given in the following table.

First String Second String Unique Merged

"program" "grammar" "programmar"

"program" "moon" "programoon"

"abc" "def" "abcdef"

"abcde" "abc" "abcdeabc"

"abcd" "abcd" "abcd"

$""$ "abc" "abc"

Complete the following function that performs unique merge on two strings. The first string is given in the parameter A$,$ and the second string is given in the parameter B$.$ The resulting string is stored in A$.$ Assume that A has sufficient space to store the merged string. Assume also that the maximum length of the strings is $1024.$