import java.util.Scanner;

public class Main {
	public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner(System.in);
        Main m = new Main(sc);
        m.show(m.solve());
        sc.close();
    }
    
	//フィールド
    Scanner sc;
    int S;
    int W;
    
    //入力
    Main(Scanner sc) {
        this.sc = sc;
        this.S = sc.nextInt();
        this.W = sc.nextInt();
    }
    
    //解答処理
    private String solve() {
        String answer =  "safe";
        if (S <= W) {
        	answer = "unsafe";
        }
        
        return answer;
    }
    
    //出力
    public void show(String answer) {
        System.out.println(answer);
    }

} import java.util.Scanner; Scanner java.util public class Main {
	public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner(System.in);
        Main m = new Main(sc);
        m.show(m.solve());
        sc.close();
    }
    
	//フィールド
    Scanner sc;
    int S;
    int W;
    
    //入力
    Main(Scanner sc) {
        this.sc = sc;
        this.S = sc.nextInt();
        this.W = sc.nextInt();
    }
    
    //解答処理
    private String solve() {
        String answer =  "safe";
        if (S <= W) {
        	answer = "unsafe";
        }
        
        return answer;
    }
    
    //出力
    public void show(String answer) {
        System.out.println(answer);
    }

} Main //フィールド
    Scanner sc; sc int S; S int W; W public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner(System.in);
        Main m = new Main(sc);
        m.show(m.solve());
        sc.close();
    } main {
        Scanner sc = new Scanner(System.in);
        Main m = new Main(sc);
        m.show(m.solve());
        sc.close();
    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) Main m = new Main(sc); m new Main(sc) m.show(m.solve()) m.show m m.solve() m.solve m sc.close() sc.close sc String[] args args //入力
    Main(Scanner sc) {
        this.sc = sc;
        this.S = sc.nextInt();
        this.W = sc.nextInt();
    } Main {
        this.sc = sc;
        this.S = sc.nextInt();
        this.W = sc.nextInt();
    } this.sc = sc this.sc this this.sc sc this.S = sc.nextInt() this.S this this.S sc.nextInt() sc.nextInt sc this.W = sc.nextInt() this.W this this.W sc.nextInt() sc.nextInt sc Scanner sc sc //解答処理
    private String solve() {
        String answer =  "safe";
        if (S <= W) {
        	answer = "unsafe";
        }
        
        return answer;
    } solve {
        String answer =  "safe";
        if (S <= W) {
        	answer = "unsafe";
        }
        
        return answer;
    } String answer =  "safe"; answer "safe" if (S <= W) {
        	answer = "unsafe";
        } S <= W S W {
        	answer = "unsafe";
        } answer = "unsafe" answer "unsafe" return answer; answer //出力
    public void show(String answer) {
        System.out.println(answer);
    } show {
        System.out.println(answer);
    } System.out.println(answer) System.out.println System.out System System.out answer String answer answer public class Main {
	public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner(System.in);
        Main m = new Main(sc);
        m.show(m.solve());
        sc.close();
    }
    
	//フィールド
    Scanner sc;
    int S;
    int W;
    
    //入力
    Main(Scanner sc) {
        this.sc = sc;
        this.S = sc.nextInt();
        this.W = sc.nextInt();
    }
    
    //解答処理
    private String solve() {
        String answer =  "safe";
        if (S <= W) {
        	answer = "unsafe";
        }
        
        return answer;
    }
    
    //出力
    public void show(String answer) {
        System.out.println(answer);
    }

} public class Main {
	public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner(System.in);
        Main m = new Main(sc);
        m.show(m.solve());
        sc.close();
    }
    
	//フィールド
    Scanner sc;
    int S;
    int W;
    
    //入力
    Main(Scanner sc) {
        this.sc = sc;
        this.S = sc.nextInt();
        this.W = sc.nextInt();
    }
    
    //解答処理
    private String solve() {
        String answer =  "safe";
        if (S <= W) {
        	answer = "unsafe";
        }
        
        return answer;
    }
    
    //出力
    public void show(String answer) {
        System.out.println(answer);
    }

} Main
import java.util.Scanner;

public class Main {
	public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner(System.in);
        Main m = new Main(sc);
        m.show(m.solve());
        sc.close();
    }
    
	//フィールド
    Scanner sc;
    int S;
    int W;
    
    //入力
    Main(Scanner sc) {
        this.sc = sc;
        this.S = sc.nextInt();
        this.W = sc.nextInt();
    }
    
    //解答処理
    private String solve() {
        String answer =  "safe";
        if (S <= W) {
        	answer = "unsafe";
        }
        
        return answer;
    }
    
    //出力
    public void show(String answer) {
        System.out.println(answer);
    }

}
