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 PHP (7.4.4) (judge verdict: Accepted)

<?php
//error_reporting(0);
//$N = (int)trim(fgets(STDIN));
//$R = trim(fgets(STDIN));
list($S,$W) = array_map('intval',explode(" ",trim(fgets(STDIN))));
//$s = trim(fgets(STDIN));
//$A = array_map('intval',explode(" ",trim(fgets(STDIN))));

if ($W >= $S) {
  printf("unsafe\n");
}
else {
  printf("safe\n");
}