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 Java (OpenJDK 11.0.6) (judge verdict: Runtime Error)

import java.util.*;

public class Main {
  public static void main(String[] args) {
          Scanner sc = new Scanner(System.in);
          int hp1 = sc.nextInt();
          int attack1 = sc.nextInt();
          int hp2 = sc.nextInt();
          int attack2 = sc.nextInt();
          while(hp1 > 0 || hp2 > 0){
            hp2 -= attack1;
          if(hp2 <= 0) {
            System.out.println("Yes");

            hp1 -= attack2;
          if(hp1 <= 0) {
            System.out.println("No");
          }
          }
          }
        }
  }