import java.util.Scanner;
public class Main {
    public static void main(String[] args) throws Exception {
        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.Scanner; Scanner java.util public class Main {
    public static void main(String[] args) throws Exception {
        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 public static void main(String[] args) throws Exception {
        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 public class Main {
    public static void main(String[] args) throws Exception {
        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");
        }
        
    }
    
} public class Main {
    public static void main(String[] args) throws Exception {
        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
import java.util.Scanner;
public class Main {
    public static void main(String[] args) throws Exception {
        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");
        }
        
    }
    
}