import java.util.Scanner;

public class Main {

	public static void main(String[] args) {

				Scanner sc = new Scanner(System.in);

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

				if(wolf >= sheep) {
					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 sc = new Scanner(System.in);

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

				if(wolf >= sheep) {
					System.out.println("unsafe");
				}else {
					System.out.println("safe");
				}
			}
		} Main public static void main(String[] args) {

				Scanner sc = new Scanner(System.in);

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

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

				Scanner sc = new Scanner(System.in);

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

				if(wolf >= sheep) {
					System.out.println("unsafe");
				}else {
					System.out.println("safe");
				}
			} Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int sheep = sc.nextInt(); sheep sc.nextInt() sc.nextInt sc int wolf = sc.nextInt(); wolf sc.nextInt() sc.nextInt sc if(wolf >= sheep) {
					System.out.println("unsafe");
				}else {
					System.out.println("safe");
				} wolf >= sheep wolf sheep {
					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 sc = new Scanner(System.in);

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

				if(wolf >= sheep) {
					System.out.println("unsafe");
				}else {
					System.out.println("safe");
				}
			}
		} public class Main {

	public static void main(String[] args) {

				Scanner sc = new Scanner(System.in);

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

				if(wolf >= sheep) {
					System.out.println("unsafe");
				}else {
					System.out.println("safe");
				}
			}
		} Main
import java.util.Scanner;

public class Main {

	public static void main(String[] args) {

				Scanner sc = new Scanner(System.in);

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

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