Background

Description

Given 2 strings, a and b, return a new string made of the first char of a and the last char of b, so "yo" and "java" yields "ya". If either string is length 0, use '@' for its missing char.

Format

Input

Output

Samples

last" "chars

"ls"

yo" "java

"ya"

hi" "

"h@"

Limitation

1s, 1024KiB for each test case.