#描述#
You have two strings, s and t, and you want them to be equal. You can change individual letters in the strings, but you cannot add or remove letters. In a single move, you can change any one letter in one string to the letter that comes directly before or after it in the alphabet. The alphabet wraps around, so you can also change 'a' to 'z' or 'z' to 'a'. You want to make the two strings equal using the minimum possible number of moves. find the resulting string. If there are multiple answers, find the one that comes earliest alphabetically.

#格式#
##输入格式##
Multi case
Every case contain two strings(same length) , one per line.
Process to the end of the file

##输出格式##
One string said above.

#样例1#
##样例输入1##

cat
dog

##样例输出1##

caa

#限制#
1000ms
32768KB

#提示#

#来源#
zjut_DD