import java.util.Scanner;

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

                int sheep = scan.nextInt();
                int wolf = scan.nextInt();

                if (sheep <= wolf) {
                	System.out.println("unsafe");
                } else {
                	System.out.println("safe");
                }

        }

} import java.util.Scanner; Scanner java.util public class Main {
        public static void main(String[] args) {
                Scanner scan = new Scanner(System.in);

                int sheep = scan.nextInt();
                int wolf = scan.nextInt();

                if (sheep <= wolf) {
                	System.out.println("unsafe");
                } else {
                	System.out.println("safe");
                }

        }

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

                int sheep = scan.nextInt();
                int wolf = scan.nextInt();

                if (sheep <= wolf) {
                	System.out.println("unsafe");
                } else {
                	System.out.println("safe");
                }

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

                int sheep = scan.nextInt();
                int wolf = scan.nextInt();

                if (sheep <= wolf) {
                	System.out.println("unsafe");
                } else {
                	System.out.println("safe");
                }

        } Scanner scan = new Scanner(System.in); scan new Scanner(System.in) int sheep = scan.nextInt(); sheep scan.nextInt() scan.nextInt scan int wolf = scan.nextInt(); wolf scan.nextInt() scan.nextInt scan if (sheep <= wolf) {
                	System.out.println("unsafe");
                } else {
                	System.out.println("safe");
                } sheep <= wolf sheep wolf {
                	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" String[] args args public class Main {
        public static void main(String[] args) {
                Scanner scan = new Scanner(System.in);

                int sheep = scan.nextInt();
                int wolf = scan.nextInt();

                if (sheep <= wolf) {
                	System.out.println("unsafe");
                } else {
                	System.out.println("safe");
                }

        }

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

                int sheep = scan.nextInt();
                int wolf = scan.nextInt();

                if (sheep <= wolf) {
                	System.out.println("unsafe");
                } else {
                	System.out.println("safe");
                }

        }

} Main
import java.util.Scanner;

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

                int sheep = scan.nextInt();
                int wolf = scan.nextInt();

                if (sheep <= wolf) {
                	System.out.println("unsafe");
                } else {
                	System.out.println("safe");
                }

        }

}