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: Wrong Answer)

$input_line = trim(fgets(STDIN));
    
    $ans = explode(" ",$input_line);
    
    //print_r($ans);
    
    if($ans[0]>$ans[1]){
        echo "safe";
    }elseif($ans[0]<=$ans[1]){
        echo "unsafe";
    }