Back and Forth

Steve has hit the jackpot at his local flea market. He bought a cheap scanner with a special ability: it detects palindrome words! Unfortunately the algorithm that checks the words is broken, thus Steve asked you to write a new algorithm to implement in the scanner and revive it's glory once more.

Remember that a palindrome word is a word that reads the same when reversed: racecar for example is a palindrome.

The input consists of a string s, having length $1 \leq |s| \leq 1000000$.

Your program should output "beep" if the string s is a palindrome, "boop" otherwise.