import java.util.*;

public class Main {
    public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner(System.in);
        String data = sc.nextLine();
        
        String[] array = data.split(" ");
        int s = Integer.parseInt(array[0]);
        int w = Integer.parseInt(array[1]);
        
        String result = "safe";
        
        if(w >= s)
        {
            result = "unsafe";
        }
        
        System.out.println(result);
    }
} import java.util.*; util.* java public class Main {
    public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner(System.in);
        String data = sc.nextLine();
        
        String[] array = data.split(" ");
        int s = Integer.parseInt(array[0]);
        int w = Integer.parseInt(array[1]);
        
        String result = "safe";
        
        if(w >= s)
        {
            result = "unsafe";
        }
        
        System.out.println(result);
    }
} Main public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner(System.in);
        String data = sc.nextLine();
        
        String[] array = data.split(" ");
        int s = Integer.parseInt(array[0]);
        int w = Integer.parseInt(array[1]);
        
        String result = "safe";
        
        if(w >= s)
        {
            result = "unsafe";
        }
        
        System.out.println(result);
    } main {
        Scanner sc = new Scanner(System.in);
        String data = sc.nextLine();
        
        String[] array = data.split(" ");
        int s = Integer.parseInt(array[0]);
        int w = Integer.parseInt(array[1]);
        
        String result = "safe";
        
        if(w >= s)
        {
            result = "unsafe";
        }
        
        System.out.println(result);
    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) String data = sc.nextLine(); data sc.nextLine() sc.nextLine sc String[] array = data.split(" "); array data.split(" ") data.split data " " int s = Integer.parseInt(array[0]); s Integer.parseInt(array[0]) Integer.parseInt Integer array[0] array 0 int w = Integer.parseInt(array[1]); w Integer.parseInt(array[1]) Integer.parseInt Integer array[1] array 1 String result = "safe"; result "safe" if(w >= s)
        {
            result = "unsafe";
        } w >= s w s {
            result = "unsafe";
        } result = "unsafe" result "unsafe" System.out.println(result) System.out.println System.out System System.out result String[] args args public class Main {
    public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner(System.in);
        String data = sc.nextLine();
        
        String[] array = data.split(" ");
        int s = Integer.parseInt(array[0]);
        int w = Integer.parseInt(array[1]);
        
        String result = "safe";
        
        if(w >= s)
        {
            result = "unsafe";
        }
        
        System.out.println(result);
    }
} public class Main {
    public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner(System.in);
        String data = sc.nextLine();
        
        String[] array = data.split(" ");
        int s = Integer.parseInt(array[0]);
        int w = Integer.parseInt(array[1]);
        
        String result = "safe";
        
        if(w >= s)
        {
            result = "unsafe";
        }
        
        System.out.println(result);
    }
} Main
import java.util.*;

public class Main {
    public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner(System.in);
        String data = sc.nextLine();
        
        String[] array = data.split(" ");
        int s = Integer.parseInt(array[0]);
        int w = Integer.parseInt(array[1]);
        
        String result = "safe";
        
        if(w >= s)
        {
            result = "unsafe";
        }
        
        System.out.println(result);
    }
}
