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();

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

} 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();

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

} Main public static void main(String[] args) {

		Scanner scan = new Scanner(System.in);

		int S = scan.nextInt();
		int W = scan.nextInt();

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

		Scanner scan = new Scanner(System.in);

		int S = scan.nextInt();
		int W = scan.nextInt();

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

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

} public class Main {

	public static void main(String[] args) {

		Scanner scan = new Scanner(System.in);

		int S = scan.nextInt();
		int W = scan.nextInt();

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

} 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();

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

}