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 1.8.0) (judge verdict: Runtime Error)

import java.util.*;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;

public class Main {
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);

	    int N = sc.nextInt();
        List<String> list = new ArrayList<String>();
      
      for(int i=0 ;i <= N; i++){
        String prize = sc.next();
        if(list.indexOf(prize) == -1){
          list.add(prize);
        }
      }
      
      System.out.println(list.size());
      
    }
}