import java.io.BufferedReader;
import java.io.*;
import java.util.*;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.Collections;

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

        int s = sc.nextInt();
        int w = sc.nextInt();

        if(w >= s){
            System.out.println("unsafe");
        }else{
            System.out.println("safe");
        }
        
        

        






    }
} import java.io.BufferedReader; BufferedReader java.io import java.io.*; io.* java import java.util.*; util.* java import java.util.ArrayList; ArrayList java.util import java.util.Iterator; Iterator java.util import java.util.List; List java.util import java.util.Collections; Collections java.util public class Main {
	public static void main(final String[] args){
    
        Scanner sc = new Scanner(System.in);

        int s = sc.nextInt();
        int w = sc.nextInt();

        if(w >= s){
            System.out.println("unsafe");
        }else{
            System.out.println("safe");
        }
        
        

        






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

        int s = sc.nextInt();
        int w = sc.nextInt();

        if(w >= s){
            System.out.println("unsafe");
        }else{
            System.out.println("safe");
        }
        
        

        






    } main {
    
        Scanner sc = new Scanner(System.in);

        int s = sc.nextInt();
        int w = sc.nextInt();

        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 = sc.nextInt(); s sc.nextInt() sc.nextInt sc int w = sc.nextInt(); w sc.nextInt() sc.nextInt 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" final String[] args args public class Main {
	public static void main(final String[] args){
    
        Scanner sc = new Scanner(System.in);

        int s = sc.nextInt();
        int w = sc.nextInt();

        if(w >= s){
            System.out.println("unsafe");
        }else{
            System.out.println("safe");
        }
        
        

        






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

        int s = sc.nextInt();
        int w = sc.nextInt();

        if(w >= s){
            System.out.println("unsafe");
        }else{
            System.out.println("safe");
        }
        
        

        






    }
} Main
import java.io.BufferedReader;
import java.io.*;
import java.util.*;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.Collections;

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

        int s = sc.nextInt();
        int w = sc.nextInt();

        if(w >= s){
            System.out.println("unsafe");
        }else{
            System.out.println("safe");
        }
        
        

        






    }
}