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 JavaScript (Node.js 12.16.1) (judge verdict: Wrong Answer)

// inputに入力データ全体が入る

function Main(input) {
	// 1行目がinput[0]
	input = input.split(" ");
	//文字列から10進数に変換するときはparseIntを使います
	var a = parseInt(input[0], 10);
	var b = parseInt(input[1], 10);
 　 var c = parseInt(input[2], 10);
  　var d = parseInt(input[3], 10);
    while (c>0 && a>0) {
        c=c-b;
      if (c<=0){
        break;
      }else{
        a=a-d
      }
    }
  if(a>0){
  console.log('Yes');
  }
  else {
  console.log('No');
  }
}
//*この行以降は編集しないでください（標準入出力から一度に読み込み、Mainを呼び出します）
Main(require("fs").readFileSync("/dev/stdin", "utf8"));