import java.util.*; 
import java.lang.*; 

public class Main{
	public static void main(String[] args){
		Scanner scan = new Scanner(System.in);
		
		int S = scan.nextInt();
                int W = scan.nextInt();
                
                if(S<=W){
                    System.out.println("unsafe");
                }
                else{
                    System.out.println("safe");
                }
	}
} import java.util.*; util.* java import java.lang.*; lang.* java public class Main{
	public static void main(String[] args){
		Scanner scan = new Scanner(System.in);
		
		int S = scan.nextInt();
                int W = scan.nextInt();
                
                if(S<=W){
                    System.out.println("unsafe");
                }
                else{
                    System.out.println("safe");
                }
	}
} Main public static void main(String[] args){
		Scanner scan = new Scanner(System.in);
		
		int S = scan.nextInt();
                int W = scan.nextInt();
                
                if(S<=W){
                    System.out.println("unsafe");
                }
                else{
                    System.out.println("safe");
                }
	} main {
		Scanner scan = new Scanner(System.in);
		
		int S = scan.nextInt();
                int W = scan.nextInt();
                
                if(S<=W){
                    System.out.println("unsafe");
                }
                else{
                    System.out.println("safe");
                }
	} Scanner scan = new Scanner(System.in); scan new Scanner(System.in) int S = scan.nextInt(); S scan.nextInt() scan.nextInt scan int W = scan.nextInt(); W scan.nextInt() scan.nextInt scan if(S<=W){
                    System.out.println("unsafe");
                }
                else{
                    System.out.println("safe");
                } S<=W S W {
                    System.out.println("unsafe");
                } System.out.println("unsafe") System.out.println System.out System System.out "unsafe" {
                    System.out.println("safe");
                } System.out.println("safe") System.out.println System.out System System.out "safe" String[] args args public class Main{
	public static void main(String[] args){
		Scanner scan = new Scanner(System.in);
		
		int S = scan.nextInt();
                int W = scan.nextInt();
                
                if(S<=W){
                    System.out.println("unsafe");
                }
                else{
                    System.out.println("safe");
                }
	}
} public class Main{
	public static void main(String[] args){
		Scanner scan = new Scanner(System.in);
		
		int S = scan.nextInt();
                int W = scan.nextInt();
                
                if(S<=W){
                    System.out.println("unsafe");
                }
                else{
                    System.out.println("safe");
                }
	}
} Main
import java.util.*; 
import java.lang.*; 

public class Main{
	public static void main(String[] args){
		Scanner scan = new Scanner(System.in);
		
		int S = scan.nextInt();
                int W = scan.nextInt();
                
                if(S<=W){
                    System.out.println("unsafe");
                }
                else{
                    System.out.println("safe");
                }
	}
}