import java.util.*;
import java.util.Map.Entry;
 
 
 class Main {
	 static int mod =  (int) (Math.pow(10,9)+7);
	 static List<ArrayList<Integer>>  list = new ArrayList<ArrayList<Integer>>();
    public static void main(String[] args) {
    
        Scanner sc = new Scanner(System.in);
    	int S = sc.nextInt();
    	int W = sc.nextInt();
    	if(S>W) {
    		System.out.println("safe");
    	} else {
    		System.out.println("unsafe");
    	}
    	 
    	
    	
    	
    	
        		
    }
} import java.util.*; util.* java import java.util.Map.Entry; Entry java.util.Map class Main {
	 static int mod =  (int) (Math.pow(10,9)+7);
	 static List<ArrayList<Integer>>  list = new ArrayList<ArrayList<Integer>>();
    public static void main(String[] args) {
    
        Scanner sc = new Scanner(System.in);
    	int S = sc.nextInt();
    	int W = sc.nextInt();
    	if(S>W) {
    		System.out.println("safe");
    	} else {
    		System.out.println("unsafe");
    	}
    	 
    	
    	
    	
    	
        		
    }
} Main static int mod =  (int) (Math.pow(10,9)+7); mod (int) (Math.pow(10,9)+7) Math.pow(10,9) Math.pow Math 10 9 7 static List<ArrayList<Integer>>  list = new ArrayList<ArrayList<Integer>>(); list new ArrayList<ArrayList<Integer>>() public static void main(String[] args) {
    
        Scanner sc = new Scanner(System.in);
    	int S = sc.nextInt();
    	int W = sc.nextInt();
    	if(S>W) {
    		System.out.println("safe");
    	} else {
    		System.out.println("unsafe");
    	}
    	 
    	
    	
    	
    	
        		
    } main {
    
        Scanner sc = new Scanner(System.in);
    	int S = sc.nextInt();
    	int W = sc.nextInt();
    	if(S>W) {
    		System.out.println("safe");
    	} else {
    		System.out.println("unsafe");
    	}
    	 
    	
    	
    	
    	
        		
    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int S = sc.nextInt(); S sc.nextInt() sc.nextInt sc int W = sc.nextInt(); W sc.nextInt() sc.nextInt sc if(S>W) {
    		System.out.println("safe");
    	} else {
    		System.out.println("unsafe");
    	} S>W S W {
    		System.out.println("safe");
    	} System.out.println("safe") System.out.println System.out System System.out "safe" {
    		System.out.println("unsafe");
    	} System.out.println("unsafe") System.out.println System.out System System.out "unsafe" String[] args args
import java.util.*;
import java.util.Map.Entry;
 
 
 class Main {
	 static int mod =  (int) (Math.pow(10,9)+7);
	 static List<ArrayList<Integer>>  list = new ArrayList<ArrayList<Integer>>();
    public static void main(String[] args) {
    
        Scanner sc = new Scanner(System.in);
    	int S = sc.nextInt();
    	int W = sc.nextInt();
    	if(S>W) {
    		System.out.println("safe");
    	} else {
    		System.out.println("unsafe");
    	}
    	 
    	
    	
    	
    	
        		
    }
}