import java.util.Scanner;

public class Main{
 public static void main(String[] args){
  Scanner sc = new Scanner(System.in);
  int sheep = sc.nextInt(), wolf=sc.nextInt();
  if(wolf>=sheep) System.out.println("unsafe");
  else System.out.println("safe");
 }
}
		 import java.util.Scanner; Scanner java.util public class Main{
 public static void main(String[] args){
  Scanner sc = new Scanner(System.in);
  int sheep = sc.nextInt(), wolf=sc.nextInt();
  if(wolf>=sheep) System.out.println("unsafe");
  else System.out.println("safe");
 }
} Main public static void main(String[] args){
  Scanner sc = new Scanner(System.in);
  int sheep = sc.nextInt(), wolf=sc.nextInt();
  if(wolf>=sheep) System.out.println("unsafe");
  else System.out.println("safe");
 } main {
  Scanner sc = new Scanner(System.in);
  int sheep = sc.nextInt(), wolf=sc.nextInt();
  if(wolf>=sheep) System.out.println("unsafe");
  else System.out.println("safe");
 } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int sheep = sc.nextInt() sheep sc.nextInt() sc.nextInt sc wolf=sc.nextInt(); wolf sc.nextInt() sc.nextInt sc if(wolf>=sheep) System.out.println("unsafe");
  else System.out.println("safe"); wolf>=sheep wolf sheep System.out.println("unsafe") System.out.println System.out System System.out "unsafe" System.out.println("safe") System.out.println System.out System System.out "safe" String[] args args public class Main{
 public static void main(String[] args){
  Scanner sc = new Scanner(System.in);
  int sheep = sc.nextInt(), wolf=sc.nextInt();
  if(wolf>=sheep) System.out.println("unsafe");
  else System.out.println("safe");
 }
} public class Main{
 public static void main(String[] args){
  Scanner sc = new Scanner(System.in);
  int sheep = sc.nextInt(), wolf=sc.nextInt();
  if(wolf>=sheep) System.out.println("unsafe");
  else System.out.println("safe");
 }
} Main
import java.util.Scanner;

public class Main{
 public static void main(String[] args){
  Scanner sc = new Scanner(System.in);
  int sheep = sc.nextInt(), wolf=sc.nextInt();
  if(wolf>=sheep) System.out.println("unsafe");
  else System.out.println("safe");
 }
}
		