import java.util.Scanner;

class Main {
	// ABC164 A
	public static void main(String[] args) {

		Scanner sc = new Scanner(System.in);

		int S = Integer.parseInt(sc.next());
		int W = Integer.parseInt(sc.next());


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

} import java.util.Scanner; Scanner java.util class Main {
	// ABC164 A
	public static void main(String[] args) {

		Scanner sc = new Scanner(System.in);

		int S = Integer.parseInt(sc.next());
		int W = Integer.parseInt(sc.next());


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

} Main // ABC164 A
	public static void main(String[] args) {

		Scanner sc = new Scanner(System.in);

		int S = Integer.parseInt(sc.next());
		int W = Integer.parseInt(sc.next());


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

		Scanner sc = new Scanner(System.in);

		int S = Integer.parseInt(sc.next());
		int W = Integer.parseInt(sc.next());


		if(S > W) {
			System.out.println("safe");
		} else {
			System.out.println("unsafe");
		}
	} Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int S = Integer.parseInt(sc.next()); S Integer.parseInt(sc.next()) Integer.parseInt Integer sc.next() sc.next sc int W = Integer.parseInt(sc.next()); W Integer.parseInt(sc.next()) Integer.parseInt Integer sc.next() sc.next sc 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
import java.util.Scanner;

class Main {
	// ABC164 A
	public static void main(String[] args) {

		Scanner sc = new Scanner(System.in);

		int S = Integer.parseInt(sc.next());
		int W = Integer.parseInt(sc.next());


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

}
