import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		Scanner scanner = new Scanner(System.in);

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

		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 scanner = new Scanner(System.in);

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

		if(W >= S) {
			System.out.println("unsafe");
		}else {
			System.out.println("safe");
		}
	}
} Main public static void main(String[] args) {
		Scanner scanner = new Scanner(System.in);

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

		if(W >= S) {
			System.out.println("unsafe");
		}else {
			System.out.println("safe");
		}
	} main {
		Scanner scanner = new Scanner(System.in);

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

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

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

		if(W >= S) {
			System.out.println("unsafe");
		}else {
			System.out.println("safe");
		}
	}
} public class Main {
	public static void main(String[] args) {
		Scanner scanner = new Scanner(System.in);

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

		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 scanner = new Scanner(System.in);

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

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