import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int S = sc.nextInt(), W = sc.nextInt();
		sc.close();

		if (W >= S)
			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 S = sc.nextInt(), W = sc.nextInt();
		sc.close();

		if (W >= S)
			System.out.println("unsafe");
		else
			System.out.println("safe");
	}

} Main public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int S = sc.nextInt(), W = sc.nextInt();
		sc.close();

		if (W >= S)
			System.out.println("unsafe");
		else
			System.out.println("safe");
	} main {
		Scanner sc = new Scanner(System.in);
		int S = sc.nextInt(), W = sc.nextInt();
		sc.close();

		if (W >= S)
			System.out.println("unsafe");
		else
			System.out.println("safe");
	} Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int S = sc.nextInt() S sc.nextInt() sc.nextInt sc W = sc.nextInt(); W sc.nextInt() sc.nextInt sc sc.close() sc.close sc if (W >= S)
			System.out.println("unsafe");
		else
			System.out.println("safe"); W >= S W S System.out.println("unsafe") System.out.println System.out System System.out "unsafe" 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 S = sc.nextInt(), W = sc.nextInt();
		sc.close();

		if (W >= S)
			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 S = sc.nextInt(), W = sc.nextInt();
		sc.close();

		if (W >= S)
			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 S = sc.nextInt(), W = sc.nextInt();
		sc.close();

		if (W >= S)
			System.out.println("unsafe");
		else
			System.out.println("safe");
	}

}
