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: Accepted)

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.lang.reflect.Array;
import java.util.Scanner;
import java.util.StringTokenizer;
import java.util.*;

public class Main {

    static class FastReader{
        BufferedReader br;
        StringTokenizer st;

        public FastReader(){
            br = new BufferedReader(new InputStreamReader(System.in));
        }

        String next(){
            while(st==null || !st.hasMoreElements()){
                try{
                    st=new StringTokenizer(br.readLine());
                }
                catch(IOException e){
                    e.printStackTrace();
                }
            }
            return st.nextToken();
        }

        int nextInt(){
            return Integer.parseInt(next());
        }

        Long nextLong(){
            return Long.parseLong(next());
        }

        double nextDouble(){
            return Double.parseDouble(next());
        }
        String nextLine(){
            String str="";
            try{
                str=br.readLine();
            }
            catch(IOException e){
                e.printStackTrace();
            }
            return str;
        }
    }

    public static void main(String[] args) {
        FastReader in = new FastReader();
       int s=in.nextInt();
       int w =in.nextInt();
       if(w>=s){
           System.out.println("unsafe");
       }else{
           System.out.println("safe");
       }
    }
}