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


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


	}
} Main public static void main(String[] args)  {
		Scanner scan = new Scanner(System.in);
		int s = Integer.parseInt(scan.next());
		int w = Integer.parseInt(scan.next());
		if (s<=w){
			System.out.print("unsafe");
		}else{
			System.out.print("safe");
		}


	} main {
		Scanner scan = new Scanner(System.in);
		int s = Integer.parseInt(scan.next());
		int w = Integer.parseInt(scan.next());
		if (s<=w){
			System.out.print("unsafe");
		}else{
			System.out.print("safe");
		}


	} Scanner scan = new Scanner(System.in); scan new Scanner(System.in) int s = Integer.parseInt(scan.next()); s Integer.parseInt(scan.next()) Integer.parseInt Integer scan.next() scan.next scan int w = Integer.parseInt(scan.next()); w Integer.parseInt(scan.next()) Integer.parseInt Integer scan.next() scan.next scan if (s<=w){
			System.out.print("unsafe");
		}else{
			System.out.print("safe");
		} s<=w s w {
			System.out.print("unsafe");
		} System.out.print("unsafe") System.out.print System.out System System.out "unsafe" {
			System.out.print("safe");
		} System.out.print("safe") System.out.print System.out System System.out "safe" String[] args args public class Main {
	public static void main(String[] args)  {
		Scanner scan = new Scanner(System.in);
		int s = Integer.parseInt(scan.next());
		int w = Integer.parseInt(scan.next());
		if (s<=w){
			System.out.print("unsafe");
		}else{
			System.out.print("safe");
		}


	}
} public class Main {
	public static void main(String[] args)  {
		Scanner scan = new Scanner(System.in);
		int s = Integer.parseInt(scan.next());
		int w = Integer.parseInt(scan.next());
		if (s<=w){
			System.out.print("unsafe");
		}else{
			System.out.print("safe");
		}


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


	}
}
//end
