import java.util.Scanner;

public class Main{
  public static void main(String args[]){
    
    Scanner scan;
    int sheep;
    int wolves;
    
    sheep = 0;
    wolves = 0;
    
    scan = new Scanner(System.in);
    sheep = scan.nextInt();
    wolves = scan.nextInt();
    
    if (sheep > wolves){
      System.out.println("safe");
    }else {
      System.out.println("unsafe");
    }
      
  }
} import java.util.Scanner; Scanner java.util public class Main{
  public static void main(String args[]){
    
    Scanner scan;
    int sheep;
    int wolves;
    
    sheep = 0;
    wolves = 0;
    
    scan = new Scanner(System.in);
    sheep = scan.nextInt();
    wolves = scan.nextInt();
    
    if (sheep > wolves){
      System.out.println("safe");
    }else {
      System.out.println("unsafe");
    }
      
  }
} Main public static void main(String args[]){
    
    Scanner scan;
    int sheep;
    int wolves;
    
    sheep = 0;
    wolves = 0;
    
    scan = new Scanner(System.in);
    sheep = scan.nextInt();
    wolves = scan.nextInt();
    
    if (sheep > wolves){
      System.out.println("safe");
    }else {
      System.out.println("unsafe");
    }
      
  } main {
    
    Scanner scan;
    int sheep;
    int wolves;
    
    sheep = 0;
    wolves = 0;
    
    scan = new Scanner(System.in);
    sheep = scan.nextInt();
    wolves = scan.nextInt();
    
    if (sheep > wolves){
      System.out.println("safe");
    }else {
      System.out.println("unsafe");
    }
      
  } Scanner scan; scan int sheep; sheep int wolves; wolves sheep = 0 sheep 0 wolves = 0 wolves 0 scan = new Scanner(System.in) scan new Scanner(System.in) sheep = scan.nextInt() sheep scan.nextInt() scan.nextInt scan wolves = scan.nextInt() wolves scan.nextInt() scan.nextInt scan if (sheep > wolves){
      System.out.println("safe");
    }else {
      System.out.println("unsafe");
    } sheep > wolves sheep wolves {
      System.out.println("safe");
    } System.out.println("safe") System.out.println System.out System System.out "safe" {
      System.out.println("unsafe");
    } System.out.println("unsafe") System.out.println System.out System System.out "unsafe" String args[] args public class Main{
  public static void main(String args[]){
    
    Scanner scan;
    int sheep;
    int wolves;
    
    sheep = 0;
    wolves = 0;
    
    scan = new Scanner(System.in);
    sheep = scan.nextInt();
    wolves = scan.nextInt();
    
    if (sheep > wolves){
      System.out.println("safe");
    }else {
      System.out.println("unsafe");
    }
      
  }
} public class Main{
  public static void main(String args[]){
    
    Scanner scan;
    int sheep;
    int wolves;
    
    sheep = 0;
    wolves = 0;
    
    scan = new Scanner(System.in);
    sheep = scan.nextInt();
    wolves = scan.nextInt();
    
    if (sheep > wolves){
      System.out.println("safe");
    }else {
      System.out.println("unsafe");
    }
      
  }
} Main
import java.util.Scanner;

public class Main{
  public static void main(String args[]){
    
    Scanner scan;
    int sheep;
    int wolves;
    
    sheep = 0;
    wolves = 0;
    
    scan = new Scanner(System.in);
    sheep = scan.nextInt();
    wolves = scan.nextInt();
    
    if (sheep > wolves){
      System.out.println("safe");
    }else {
      System.out.println("unsafe");
    }
      
  }
}
