import java.util.*;

public class Main {
	public static void main(String[] args) throws Exception{
		Scanner scn = new Scanner(System.in);
		int s = scn.nextInt();
		int w = scn.nextInt();
      	String ans="safe";
      	if(w>=s) ans="unsafe";
      	System.out.println(ans);
	}
} import java.util.*; util.* java public class Main {
	public static void main(String[] args) throws Exception{
		Scanner scn = new Scanner(System.in);
		int s = scn.nextInt();
		int w = scn.nextInt();
      	String ans="safe";
      	if(w>=s) ans="unsafe";
      	System.out.println(ans);
	}
} Main public static void main(String[] args) throws Exception{
		Scanner scn = new Scanner(System.in);
		int s = scn.nextInt();
		int w = scn.nextInt();
      	String ans="safe";
      	if(w>=s) ans="unsafe";
      	System.out.println(ans);
	} main {
		Scanner scn = new Scanner(System.in);
		int s = scn.nextInt();
		int w = scn.nextInt();
      	String ans="safe";
      	if(w>=s) ans="unsafe";
      	System.out.println(ans);
	} Scanner scn = new Scanner(System.in); scn new Scanner(System.in) int s = scn.nextInt(); s scn.nextInt() scn.nextInt scn int w = scn.nextInt(); w scn.nextInt() scn.nextInt scn String ans="safe"; ans "safe" if(w>=s) ans="unsafe"; w>=s w s ans="unsafe" ans "unsafe" System.out.println(ans) System.out.println System.out System System.out ans String[] args args public class Main {
	public static void main(String[] args) throws Exception{
		Scanner scn = new Scanner(System.in);
		int s = scn.nextInt();
		int w = scn.nextInt();
      	String ans="safe";
      	if(w>=s) ans="unsafe";
      	System.out.println(ans);
	}
} public class Main {
	public static void main(String[] args) throws Exception{
		Scanner scn = new Scanner(System.in);
		int s = scn.nextInt();
		int w = scn.nextInt();
      	String ans="safe";
      	if(w>=s) ans="unsafe";
      	System.out.println(ans);
	}
} Main
import java.util.*;

public class Main {
	public static void main(String[] args) throws Exception{
		Scanner scn = new Scanner(System.in);
		int s = scn.nextInt();
		int w = scn.nextInt();
      	String ans="safe";
      	if(w>=s) ans="unsafe";
      	System.out.println(ans);
	}
}