import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int sheep = Integer.parseInt(sc.next());
		int walf = Integer.parseInt(sc.next());
		String result =sheep > walf?"safe":"unsafe";
		System.out.println(result);

	}

} import java.util.Scanner; Scanner java.util public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int sheep = Integer.parseInt(sc.next());
		int walf = Integer.parseInt(sc.next());
		String result =sheep > walf?"safe":"unsafe";
		System.out.println(result);

	}

} Main public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int sheep = Integer.parseInt(sc.next());
		int walf = Integer.parseInt(sc.next());
		String result =sheep > walf?"safe":"unsafe";
		System.out.println(result);

	} main {
		Scanner sc = new Scanner(System.in);
		int sheep = Integer.parseInt(sc.next());
		int walf = Integer.parseInt(sc.next());
		String result =sheep > walf?"safe":"unsafe";
		System.out.println(result);

	} Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int sheep = Integer.parseInt(sc.next()); sheep Integer.parseInt(sc.next()) Integer.parseInt Integer sc.next() sc.next sc int walf = Integer.parseInt(sc.next()); walf Integer.parseInt(sc.next()) Integer.parseInt Integer sc.next() sc.next sc String result =sheep > walf?"safe":"unsafe"; result sheep > walf?"safe":"unsafe" sheep > walf sheep walf "safe" "unsafe" System.out.println(result) System.out.println System.out System System.out result String[] args args public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int sheep = Integer.parseInt(sc.next());
		int walf = Integer.parseInt(sc.next());
		String result =sheep > walf?"safe":"unsafe";
		System.out.println(result);

	}

} public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int sheep = Integer.parseInt(sc.next());
		int walf = Integer.parseInt(sc.next());
		String result =sheep > walf?"safe":"unsafe";
		System.out.println(result);

	}

} Main
import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int sheep = Integer.parseInt(sc.next());
		int walf = Integer.parseInt(sc.next());
		String result =sheep > walf?"safe":"unsafe";
		System.out.println(result);

	}

}
