Rotary Lock Next Notch

A rotary combination lock has a ring of notches engraved with lowercase letters. Reading clockwise starting from a fixed reference point, the engraved letters appear in non-decreasing alphabetical order (the same letter may be engraved on more than one notch). A locksmith rests a pointer on a target letter — which does not have to match any notch on the ring — and needs to know which engraved letter sits on the very next notch strictly past it when turning clockwise. Because the ring is circular, if no engraved letter is alphabetically greater than the target, the search wraps around and the answer is the very first engraved letter on the ring.

Input format

• Line 1: a string notches of lowercase English letters (2 <= length <= 10000), sorted in non-decreasing order, representing the letters engraved on the ring read clockwise from the reference point.
• Line 2: a single lowercase English letter target.

Output format

Print the single letter engraved on the next notch strictly clockwise past target, wrapping around to the first letter of notches if no engraved letter is greater than target.

Constraints

• 2 <= length of notches <= 10000
• notches consists only of lowercase English letters and is sorted in non-decreasing order
• target is a single lowercase English letter

cfj
a

c

cfj
c

f