import java .util.Scanner;
 
public class Main{
    public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
		int s = Integer.parseInt(sc.next());
    	int w = Integer.parseInt(sc.next());
    
 		if(w >= s){
     	 	System.out.println("unsafe");
    	}else{
      		System.out.println("safe");
    	}
    }
} import java .util.Scanner; Scanner java .util public class Main{
    public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
		int s = Integer.parseInt(sc.next());
    	int w = Integer.parseInt(sc.next());
    
 		if(w >= s){
     	 	System.out.println("unsafe");
    	}else{
      		System.out.println("safe");
    	}
    }
} Main public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
		int s = Integer.parseInt(sc.next());
    	int w = Integer.parseInt(sc.next());
    
 		if(w >= s){
     	 	System.out.println("unsafe");
    	}else{
      		System.out.println("safe");
    	}
    } main {
		Scanner sc = new Scanner(System.in);
		int s = Integer.parseInt(sc.next());
    	int w = Integer.parseInt(sc.next());
    
 		if(w >= s){
     	 	System.out.println("unsafe");
    	}else{
      		System.out.println("safe");
    	}
    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int s = Integer.parseInt(sc.next()); s Integer.parseInt(sc.next()) Integer.parseInt Integer sc.next() sc.next sc int w = Integer.parseInt(sc.next()); w Integer.parseInt(sc.next()) Integer.parseInt Integer sc.next() sc.next sc if(w >= s){
     	 	System.out.println("unsafe");
    	}else{
      		System.out.println("safe");
    	} w >= s w s {
     	 	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 sc = new Scanner(System.in);
		int s = Integer.parseInt(sc.next());
    	int w = Integer.parseInt(sc.next());
    
 		if(w >= s){
     	 	System.out.println("unsafe");
    	}else{
      		System.out.println("safe");
    	}
    }
} public class Main{
    public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
		int s = Integer.parseInt(sc.next());
    	int w = Integer.parseInt(sc.next());
    
 		if(w >= s){
     	 	System.out.println("unsafe");
    	}else{
      		System.out.println("safe");
    	}
    }
} Main
import java .util.Scanner;
 
public class Main{
    public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
		int s = Integer.parseInt(sc.next());
    	int w = Integer.parseInt(sc.next());
    
 		if(w >= s){
     	 	System.out.println("unsafe");
    	}else{
      		System.out.println("safe");
    	}
    }
}