import java.util.Scanner;

public class Main {

	void run() {
		try (Scanner sc = new Scanner(System.in)) {
			int s = sc.nextInt();
			int w = sc.nextInt();
			System.out.println(w >= s ? "unsafe" : "safe");
		}
	}

	public static void main(String[] args) {
		new Main().run();
	}

} import java.util.Scanner; Scanner java.util public class Main {

	void run() {
		try (Scanner sc = new Scanner(System.in)) {
			int s = sc.nextInt();
			int w = sc.nextInt();
			System.out.println(w >= s ? "unsafe" : "safe");
		}
	}

	public static void main(String[] args) {
		new Main().run();
	}

} Main void run() {
		try (Scanner sc = new Scanner(System.in)) {
			int s = sc.nextInt();
			int w = sc.nextInt();
			System.out.println(w >= s ? "unsafe" : "safe");
		}
	} run {
		try (Scanner sc = new Scanner(System.in)) {
			int s = sc.nextInt();
			int w = sc.nextInt();
			System.out.println(w >= s ? "unsafe" : "safe");
		}
	} try (Scanner sc = new Scanner(System.in)) {
			int s = sc.nextInt();
			int w = sc.nextInt();
			System.out.println(w >= s ? "unsafe" : "safe");
		} {
			int s = sc.nextInt();
			int w = sc.nextInt();
			System.out.println(w >= s ? "unsafe" : "safe");
		} Scanner sc = new Scanner(System.in) Scanner sc = new Scanner(System.in) new Scanner(System.in) int s = sc.nextInt(); s sc.nextInt() sc.nextInt sc int w = sc.nextInt(); w sc.nextInt() sc.nextInt sc 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" public static void main(String[] args) {
		new Main().run();
	} main {
		new Main().run();
	} new Main().run() new Main().run new Main() String[] args args public class Main {

	void run() {
		try (Scanner sc = new Scanner(System.in)) {
			int s = sc.nextInt();
			int w = sc.nextInt();
			System.out.println(w >= s ? "unsafe" : "safe");
		}
	}

	public static void main(String[] args) {
		new Main().run();
	}

} public class Main {

	void run() {
		try (Scanner sc = new Scanner(System.in)) {
			int s = sc.nextInt();
			int w = sc.nextInt();
			System.out.println(w >= s ? "unsafe" : "safe");
		}
	}

	public static void main(String[] args) {
		new Main().run();
	}

} Main
import java.util.Scanner;

public class Main {

	void run() {
		try (Scanner sc = new Scanner(System.in)) {
			int s = sc.nextInt();
			int w = sc.nextInt();
			System.out.println(w >= s ? "unsafe" : "safe");
		}
	}

	public static void main(String[] args) {
		new Main().run();
	}

}
