Problem:
Score : 100 points

Problem Statement

There are S sheep and W wolves.

If the number of wolves is greater than or equal to that of sheep, the wolves will attack the sheep.

If the wolves will attack the sheep, print unsafe; otherwise, print safe.

Constraints

1 \leq S \leq 100

1 \leq W \leq 100

Input

Input is given from Standard Input in the following format:

S W

Output

If the wolves will attack the sheep, print unsafe; otherwise, print safe.

Sample Input 1

4 5

Sample Output 1

unsafe

There are four sheep and five wolves. The number of wolves is not less than that of sheep, so they will attack them.

Sample Input 2

100 2

Sample Output 2

safe

Many a sheep drive away two wolves.

Sample Input 3

10 10

Sample Output 3

unsafe

Solution in Common Lisp (SBCL 2.0.3) (judge verdict: Accepted)

(declaim (optimize (speed 0) (safety 3) (debug 3)))
#+sbcl (declaim (sb-ext:unmuffle-conditions sb-ext:compiler-note))
;;(declaim (optimize (speed 3) (safety 0) (debug 0)))

(defvar *sheep-n* (read))
(defvar *wolf-n* (read))

(format t "~:[safe~;unsafe~]" (>= *wolf-n* *sheep-n*))