import java.util.*;

public class Main{
 	
  public static void main(String... args){
  		Scanner scanner = new Scanner(System.in);
 		int s = scanner.nextInt();
    	int w = scanner.nextInt();
    	
    	System.out.println(w>=s? "unsafe":"safe");
  }
} import java.util.*; util.* java public class Main{
 	
  public static void main(String... args){
  		Scanner scanner = new Scanner(System.in);
 		int s = scanner.nextInt();
    	int w = scanner.nextInt();
    	
    	System.out.println(w>=s? "unsafe":"safe");
  }
} Main public static void main(String... args){
  		Scanner scanner = new Scanner(System.in);
 		int s = scanner.nextInt();
    	int w = scanner.nextInt();
    	
    	System.out.println(w>=s? "unsafe":"safe");
  } main {
  		Scanner scanner = new Scanner(System.in);
 		int s = scanner.nextInt();
    	int w = scanner.nextInt();
    	
    	System.out.println(w>=s? "unsafe":"safe");
  } Scanner scanner = new Scanner(System.in); scanner new Scanner(System.in) int s = scanner.nextInt(); s scanner.nextInt() scanner.nextInt scanner int w = scanner.nextInt(); w scanner.nextInt() scanner.nextInt scanner 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 scanner = new Scanner(System.in);
 		int s = scanner.nextInt();
    	int w = scanner.nextInt();
    	
    	System.out.println(w>=s? "unsafe":"safe");
  }
} public class Main{
 	
  public static void main(String... args){
  		Scanner scanner = new Scanner(System.in);
 		int s = scanner.nextInt();
    	int w = scanner.nextInt();
    	
    	System.out.println(w>=s? "unsafe":"safe");
  }
} Main
import java.util.*;

public class Main{
 	
  public static void main(String... args){
  		Scanner scanner = new Scanner(System.in);
 		int s = scanner.nextInt();
    	int w = scanner.nextInt();
    	
    	System.out.println(w>=s? "unsafe":"safe");
  }
}