import java.util.Scanner;

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

		String message = w >= s ? "unsafe" : "safe";
		System.out.println(message);
	}

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

		String message = w >= s ? "unsafe" : "safe";
		System.out.println(message);
	}

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

		String message = w >= s ? "unsafe" : "safe";
		System.out.println(message);
	} main {
		Scanner scan = new Scanner(System.in);
		int s = scan.nextInt();
		int w = scan.nextInt();
		scan.close();

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

		String message = w >= s ? "unsafe" : "safe";
		System.out.println(message);
	}

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

		String message = w >= s ? "unsafe" : "safe";
		System.out.println(message);
	}

} Main
import java.util.Scanner;

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

		String message = w >= s ? "unsafe" : "safe";
		System.out.println(message);
	}

}