import java.util.*;

public class Main {
  public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    int S = sc.nextInt();
    int W = sc.nextInt();
    sc.close();

    boolean ans = S <= W;

    System.out.println(ans ? "unsafe" : "safe");
  }
} import java.util.*; util.* java public class Main {
  public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    int S = sc.nextInt();
    int W = sc.nextInt();
    sc.close();

    boolean ans = S <= W;

    System.out.println(ans ? "unsafe" : "safe");
  }
} Main public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    int S = sc.nextInt();
    int W = sc.nextInt();
    sc.close();

    boolean ans = S <= W;

    System.out.println(ans ? "unsafe" : "safe");
  } main {
    Scanner sc = new Scanner(System.in);
    int S = sc.nextInt();
    int W = sc.nextInt();
    sc.close();

    boolean ans = S <= W;

    System.out.println(ans ? "unsafe" : "safe");
  } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int S = sc.nextInt(); S sc.nextInt() sc.nextInt sc int W = sc.nextInt(); W sc.nextInt() sc.nextInt sc sc.close() sc.close sc boolean ans = S <= W; ans S <= W S W System.out.println(ans ? "unsafe" : "safe") System.out.println System.out System System.out ans ? "unsafe" : "safe" ans "unsafe" "safe" String[] args args public class Main {
  public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    int S = sc.nextInt();
    int W = sc.nextInt();
    sc.close();

    boolean ans = S <= W;

    System.out.println(ans ? "unsafe" : "safe");
  }
} public class Main {
  public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    int S = sc.nextInt();
    int W = sc.nextInt();
    sc.close();

    boolean ans = S <= W;

    System.out.println(ans ? "unsafe" : "safe");
  }
} Main
import java.util.*;

public class Main {
  public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    int S = sc.nextInt();
    int W = sc.nextInt();
    sc.close();

    boolean ans = S <= W;

    System.out.println(ans ? "unsafe" : "safe");
  }
}
