import java.util.*;

public class Main {
    public static void main(String[] args) throws Exception {
        String[] lines = getStdin();
        String str = lines[0];
        String[] str1 = str.split(" ");
        int sheep = Integer.parseInt(str1[0]);
        int wolf = Integer.parseInt(str1[1]);

        if (sheep <= wolf){
            System.out.println("unsafe");
        } else {
            System.out.println("safe");
        }
    
    
        
    }
  
  private static String[] getStdin() {
    Scanner scanner = new Scanner(System.in);
    ArrayList<String> lines = new ArrayList<>();
    while (scanner.hasNext()) {
      lines.add(scanner.nextLine());
    }
    return lines.toArray(new String[lines.size()]);
  }
  
} import java.util.*; util.* java public class Main {
    public static void main(String[] args) throws Exception {
        String[] lines = getStdin();
        String str = lines[0];
        String[] str1 = str.split(" ");
        int sheep = Integer.parseInt(str1[0]);
        int wolf = Integer.parseInt(str1[1]);

        if (sheep <= wolf){
            System.out.println("unsafe");
        } else {
            System.out.println("safe");
        }
    
    
        
    }
  
  private static String[] getStdin() {
    Scanner scanner = new Scanner(System.in);
    ArrayList<String> lines = new ArrayList<>();
    while (scanner.hasNext()) {
      lines.add(scanner.nextLine());
    }
    return lines.toArray(new String[lines.size()]);
  }
  
} Main public static void main(String[] args) throws Exception {
        String[] lines = getStdin();
        String str = lines[0];
        String[] str1 = str.split(" ");
        int sheep = Integer.parseInt(str1[0]);
        int wolf = Integer.parseInt(str1[1]);

        if (sheep <= wolf){
            System.out.println("unsafe");
        } else {
            System.out.println("safe");
        }
    
    
        
    } main {
        String[] lines = getStdin();
        String str = lines[0];
        String[] str1 = str.split(" ");
        int sheep = Integer.parseInt(str1[0]);
        int wolf = Integer.parseInt(str1[1]);

        if (sheep <= wolf){
            System.out.println("unsafe");
        } else {
            System.out.println("safe");
        }
    
    
        
    } String[] lines = getStdin(); lines getStdin() getStdin String str = lines[0]; str lines[0] lines 0 String[] str1 = str.split(" "); str1 str.split(" ") str.split str " " int sheep = Integer.parseInt(str1[0]); sheep Integer.parseInt(str1[0]) Integer.parseInt Integer str1[0] str1 0 int wolf = Integer.parseInt(str1[1]); wolf Integer.parseInt(str1[1]) Integer.parseInt Integer str1[1] str1 1 if (sheep <= wolf){
            System.out.println("unsafe");
        } else {
            System.out.println("safe");
        } sheep <= wolf sheep wolf {
            System.out.println("unsafe");
        } System.out.println("unsafe") System.out.println System.out System System.out "unsafe" {
            System.out.println("safe");
        } System.out.println("safe") System.out.println System.out System System.out "safe" String[] args args private static String[] getStdin() {
    Scanner scanner = new Scanner(System.in);
    ArrayList<String> lines = new ArrayList<>();
    while (scanner.hasNext()) {
      lines.add(scanner.nextLine());
    }
    return lines.toArray(new String[lines.size()]);
  } getStdin {
    Scanner scanner = new Scanner(System.in);
    ArrayList<String> lines = new ArrayList<>();
    while (scanner.hasNext()) {
      lines.add(scanner.nextLine());
    }
    return lines.toArray(new String[lines.size()]);
  } Scanner scanner = new Scanner(System.in); scanner new Scanner(System.in) ArrayList<String> lines = new ArrayList<>(); lines new ArrayList<>() while (scanner.hasNext()) {
      lines.add(scanner.nextLine());
    } scanner.hasNext() scanner.hasNext scanner {
      lines.add(scanner.nextLine());
    } lines.add(scanner.nextLine()) lines.add lines scanner.nextLine() scanner.nextLine scanner return lines.toArray(new String[lines.size()]); lines.toArray(new String[lines.size()]) lines.toArray lines new String[lines.size()] lines.size() lines.size lines public class Main {
    public static void main(String[] args) throws Exception {
        String[] lines = getStdin();
        String str = lines[0];
        String[] str1 = str.split(" ");
        int sheep = Integer.parseInt(str1[0]);
        int wolf = Integer.parseInt(str1[1]);

        if (sheep <= wolf){
            System.out.println("unsafe");
        } else {
            System.out.println("safe");
        }
    
    
        
    }
  
  private static String[] getStdin() {
    Scanner scanner = new Scanner(System.in);
    ArrayList<String> lines = new ArrayList<>();
    while (scanner.hasNext()) {
      lines.add(scanner.nextLine());
    }
    return lines.toArray(new String[lines.size()]);
  }
  
} public class Main {
    public static void main(String[] args) throws Exception {
        String[] lines = getStdin();
        String str = lines[0];
        String[] str1 = str.split(" ");
        int sheep = Integer.parseInt(str1[0]);
        int wolf = Integer.parseInt(str1[1]);

        if (sheep <= wolf){
            System.out.println("unsafe");
        } else {
            System.out.println("safe");
        }
    
    
        
    }
  
  private static String[] getStdin() {
    Scanner scanner = new Scanner(System.in);
    ArrayList<String> lines = new ArrayList<>();
    while (scanner.hasNext()) {
      lines.add(scanner.nextLine());
    }
    return lines.toArray(new String[lines.size()]);
  }
  
} Main
import java.util.*;

public class Main {
    public static void main(String[] args) throws Exception {
        String[] lines = getStdin();
        String str = lines[0];
        String[] str1 = str.split(" ");
        int sheep = Integer.parseInt(str1[0]);
        int wolf = Integer.parseInt(str1[1]);

        if (sheep <= wolf){
            System.out.println("unsafe");
        } else {
            System.out.println("safe");
        }
    
    
        
    }
  
  private static String[] getStdin() {
    Scanner scanner = new Scanner(System.in);
    ArrayList<String> lines = new ArrayList<>();
    while (scanner.hasNext()) {
      lines.add(scanner.nextLine());
    }
    return lines.toArray(new String[lines.size()]);
  }
  
}
