import java.util.*;
public class Main {
	public static void main(String[] args)  {
		Scanner scan = new Scanner(System.in);
		int s,w;
		s = Integer.parseInt(scan.next());
		w = Integer.parseInt(scan.next());
		System.out.println(w >= s?"unsafe":"safe");
	}

}
//end import java.util.*; util.* java public class Main {
	public static void main(String[] args)  {
		Scanner scan = new Scanner(System.in);
		int s,w;
		s = Integer.parseInt(scan.next());
		w = Integer.parseInt(scan.next());
		System.out.println(w >= s?"unsafe":"safe");
	}

} Main public static void main(String[] args)  {
		Scanner scan = new Scanner(System.in);
		int s,w;
		s = Integer.parseInt(scan.next());
		w = Integer.parseInt(scan.next());
		System.out.println(w >= s?"unsafe":"safe");
	} main {
		Scanner scan = new Scanner(System.in);
		int s,w;
		s = Integer.parseInt(scan.next());
		w = Integer.parseInt(scan.next());
		System.out.println(w >= s?"unsafe":"safe");
	} Scanner scan = new Scanner(System.in); scan new Scanner(System.in) int s s w; w s = Integer.parseInt(scan.next()) s Integer.parseInt(scan.next()) Integer.parseInt Integer scan.next() scan.next scan w = Integer.parseInt(scan.next()) w Integer.parseInt(scan.next()) Integer.parseInt Integer scan.next() scan.next scan System.out.println(w >= s?"unsafe":"safe") System.out.println System.out System System.out w >= s?"unsafe":"safe" w >= s w s "unsafe" "safe" String[] args args public class Main {
	public static void main(String[] args)  {
		Scanner scan = new Scanner(System.in);
		int s,w;
		s = Integer.parseInt(scan.next());
		w = Integer.parseInt(scan.next());
		System.out.println(w >= s?"unsafe":"safe");
	}

} public class Main {
	public static void main(String[] args)  {
		Scanner scan = new Scanner(System.in);
		int s,w;
		s = Integer.parseInt(scan.next());
		w = Integer.parseInt(scan.next());
		System.out.println(w >= s?"unsafe":"safe");
	}

} Main
import java.util.*;
public class Main {
	public static void main(String[] args)  {
		Scanner scan = new Scanner(System.in);
		int s,w;
		s = Integer.parseInt(scan.next());
		w = Integer.parseInt(scan.next());
		System.out.println(w >= s?"unsafe":"safe");
	}

}
//end