Who hasn't sign up

Description

Shawn has several friends who join the leetcode contest weekly.

Now as you know , Shawn holds a contest. He knows each friend's id and he hears one of them haven't join. Could you tell him who hasn't join yet?

Every ID is a unique string which contains uppercase / lowercase / digits. Maximum length is 24.

Input

First line contains a number N ( $ 1<= N <= 10^{4}$ )

Next N lines would contain 1 unique ID , maximum length 24, which indicates the friends' ids

Next N -1 lines would contain 1 unique ID , which indicates the friends who are already joined. ( No one joins twice)

Output

Output a line which contains the ID which hasn't sign in yet.

输入样例

4
Yu
Weidong
Nero
Peng
Peng
Yu
Nero

输出样例

Weidong