import java.util.*;
import java.io.*;

public class Main {

    public static void main(String[] args) throws Exception {
        // Your code here!
        Scanner in = new Scanner(new BufferedReader(new InputStreamReader(System.in)));
        
        int S = in.nextInt();
        int W = in.nextInt();
     
        System.out.println(W >= S ? "unsafe": "safe");
    }
    

        
} import java.util.*; util.* java import java.io.*; io.* java public class Main {

    public static void main(String[] args) throws Exception {
        // Your code here!
        Scanner in = new Scanner(new BufferedReader(new InputStreamReader(System.in)));
        
        int S = in.nextInt();
        int W = in.nextInt();
     
        System.out.println(W >= S ? "unsafe": "safe");
    }
    

        
} Main public static void main(String[] args) throws Exception {
        // Your code here!
        Scanner in = new Scanner(new BufferedReader(new InputStreamReader(System.in)));
        
        int S = in.nextInt();
        int W = in.nextInt();
     
        System.out.println(W >= S ? "unsafe": "safe");
    } main {
        // Your code here!
        Scanner in = new Scanner(new BufferedReader(new InputStreamReader(System.in)));
        
        int S = in.nextInt();
        int W = in.nextInt();
     
        System.out.println(W >= S ? "unsafe": "safe");
    } Scanner in = new Scanner(new BufferedReader(new InputStreamReader(System.in))); in new Scanner(new BufferedReader(new InputStreamReader(System.in))) int S = in.nextInt(); S in.nextInt() in.nextInt in int W = in.nextInt(); W in.nextInt() in.nextInt in System.out.println(W >= S ? "unsafe": "safe") System.out.println System.out System System.out W >= S ? "unsafe": "safe" W >= S W S "unsafe" "safe" String[] args args public class Main {

    public static void main(String[] args) throws Exception {
        // Your code here!
        Scanner in = new Scanner(new BufferedReader(new InputStreamReader(System.in)));
        
        int S = in.nextInt();
        int W = in.nextInt();
     
        System.out.println(W >= S ? "unsafe": "safe");
    }
    

        
} public class Main {

    public static void main(String[] args) throws Exception {
        // Your code here!
        Scanner in = new Scanner(new BufferedReader(new InputStreamReader(System.in)));
        
        int S = in.nextInt();
        int W = in.nextInt();
     
        System.out.println(W >= S ? "unsafe": "safe");
    }
    

        
} Main
import java.util.*;
import java.io.*;

public class Main {

    public static void main(String[] args) throws Exception {
        // Your code here!
        Scanner in = new Scanner(new BufferedReader(new InputStreamReader(System.in)));
        
        int S = in.nextInt();
        int W = in.nextInt();
     
        System.out.println(W >= S ? "unsafe": "safe");
    }
    

        
}
