import java.util.Scanner;

public class Main {

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

		boolean answer = w >= s;

		printBool(answer);
	}

	public static void printBool(boolean bool) {
		print(bool ? "unsafe" : "safe");
	}

	public static void print(Object obj) {
		System.out.println(obj);
	}
} 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();
		int w = sc.nextInt();
		sc.close();

		boolean answer = w >= s;

		printBool(answer);
	}

	public static void printBool(boolean bool) {
		print(bool ? "unsafe" : "safe");
	}

	public static void print(Object obj) {
		System.out.println(obj);
	}
} Main public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int s = sc.nextInt();
		int w = sc.nextInt();
		sc.close();

		boolean answer = w >= s;

		printBool(answer);
	} main {
		Scanner sc = new Scanner(System.in);
		int s = sc.nextInt();
		int w = sc.nextInt();
		sc.close();

		boolean answer = w >= s;

		printBool(answer);
	} Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int s = sc.nextInt(); s sc.nextInt() sc.nextInt sc int w = sc.nextInt(); w sc.nextInt() sc.nextInt sc sc.close() sc.close sc boolean answer = w >= s; answer w >= s w s printBool(answer) printBool answer String[] args args public static void printBool(boolean bool) {
		print(bool ? "unsafe" : "safe");
	} printBool {
		print(bool ? "unsafe" : "safe");
	} print(bool ? "unsafe" : "safe") print bool ? "unsafe" : "safe" bool "unsafe" "safe" boolean bool bool public static void print(Object obj) {
		System.out.println(obj);
	} print {
		System.out.println(obj);
	} System.out.println(obj) System.out.println System.out System System.out obj Object obj obj public class Main {

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

		boolean answer = w >= s;

		printBool(answer);
	}

	public static void printBool(boolean bool) {
		print(bool ? "unsafe" : "safe");
	}

	public static void print(Object obj) {
		System.out.println(obj);
	}
} public class Main {

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

		boolean answer = w >= s;

		printBool(answer);
	}

	public static void printBool(boolean bool) {
		print(bool ? "unsafe" : "safe");
	}

	public static void print(Object obj) {
		System.out.println(obj);
	}
} Main
import java.util.Scanner;

public class Main {

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

		boolean answer = w >= s;

		printBool(answer);
	}

	public static void printBool(boolean bool) {
		print(bool ? "unsafe" : "safe");
	}

	public static void print(Object obj) {
		System.out.println(obj);
	}
}
