import java.util.Scanner;

public class Main {

	public static long CONST = (long) Math.pow(10, 9) + 7L;

	static Main instance = new Main();

	public static void main(String[] args) {

		Scanner scan = new Scanner(System.in);

		//入力値
		int S = scan.nextInt();
		int W = scan.nextInt();

		//WK変数

		//演算

		//結果出力
		System.out.println(S > W ? "safe" : "unsafe");
	}
} import java.util.Scanner; Scanner java.util public class Main {

	public static long CONST = (long) Math.pow(10, 9) + 7L;

	static Main instance = new Main();

	public static void main(String[] args) {

		Scanner scan = new Scanner(System.in);

		//入力値
		int S = scan.nextInt();
		int W = scan.nextInt();

		//WK変数

		//演算

		//結果出力
		System.out.println(S > W ? "safe" : "unsafe");
	}
} Main public static long CONST = (long) Math.pow(10, 9) + 7L; CONST (long) Math.pow(10, 9) + 7L (long) Math.pow(10, 9) Math.pow Math 10 9 7L static Main instance = new Main(); instance new Main() public static void main(String[] args) {

		Scanner scan = new Scanner(System.in);

		//入力値
		int S = scan.nextInt();
		int W = scan.nextInt();

		//WK変数

		//演算

		//結果出力
		System.out.println(S > W ? "safe" : "unsafe");
	} main {

		Scanner scan = new Scanner(System.in);

		//入力値
		int S = scan.nextInt();
		int W = scan.nextInt();

		//WK変数

		//演算

		//結果出力
		System.out.println(S > W ? "safe" : "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 System.out.println(S > W ? "safe" : "unsafe") System.out.println System.out System System.out S > W ? "safe" : "unsafe" S > W S W "safe" "unsafe" String[] args args public class Main {

	public static long CONST = (long) Math.pow(10, 9) + 7L;

	static Main instance = new Main();

	public static void main(String[] args) {

		Scanner scan = new Scanner(System.in);

		//入力値
		int S = scan.nextInt();
		int W = scan.nextInt();

		//WK変数

		//演算

		//結果出力
		System.out.println(S > W ? "safe" : "unsafe");
	}
} public class Main {

	public static long CONST = (long) Math.pow(10, 9) + 7L;

	static Main instance = new Main();

	public static void main(String[] args) {

		Scanner scan = new Scanner(System.in);

		//入力値
		int S = scan.nextInt();
		int W = scan.nextInt();

		//WK変数

		//演算

		//結果出力
		System.out.println(S > W ? "safe" : "unsafe");
	}
} Main
import java.util.Scanner;

public class Main {

	public static long CONST = (long) Math.pow(10, 9) + 7L;

	static Main instance = new Main();

	public static void main(String[] args) {

		Scanner scan = new Scanner(System.in);

		//入力値
		int S = scan.nextInt();
		int W = scan.nextInt();

		//WK変数

		//演算

		//結果出力
		System.out.println(S > W ? "safe" : "unsafe");
	}
}