A trail-mix vendor describes a batch as a string of lowercase letters, where each letter names one scoop of a single ingredient. To prepare a restock, the vendor takes every scoop from the original batch, shuffles their order however they like, and then mixes in exactly one additional scoop of some ingredient (which may or may not be an ingredient already in the batch).

Given the original batch string s and the restocked batch string t, where t is some shuffling of s plus exactly one extra character, determine which ingredient letter was the extra one mixed in.

Input format

Line 1: the string s (may be empty). Line 2: the string t, whose length is exactly one more than the length of s.

Output format

A single line containing the one extra lowercase letter that appears in t but was not part of the original batch s.

Constraints

• 0 <= length of s <= 1000
• length of t == length of s + 1
• s and t consist only of lowercase English letters
• t is guaranteed to be a shuffling of s with exactly one extra letter inserted

abcd
abcde

e

y

y