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();
    String ans = "safe";
    if(s <= w) ans = "unsafe";
    System.out.println(ans);
  }
} 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();
    String ans = "safe";
    if(s <= w) ans = "unsafe";
    System.out.println(ans);
  }
} Main public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    int s = sc.nextInt();
    int w = sc.nextInt();
    String ans = "safe";
    if(s <= w) ans = "unsafe";
    System.out.println(ans);
  } main {
    Scanner sc = new Scanner(System.in);
    int s = sc.nextInt();
    int w = sc.nextInt();
    String ans = "safe";
    if(s <= w) ans = "unsafe";
    System.out.println(ans);
  } 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 String ans = "safe"; ans "safe" if(s <= w) ans = "unsafe"; s <= w s w ans = "unsafe" ans "unsafe" System.out.println(ans) System.out.println System.out System System.out ans 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();
    String ans = "safe";
    if(s <= w) ans = "unsafe";
    System.out.println(ans);
  }
} public class Main {
  public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    int s = sc.nextInt();
    int w = sc.nextInt();
    String ans = "safe";
    if(s <= w) ans = "unsafe";
    System.out.println(ans);
  }
} 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();
    String ans = "safe";
    if(s <= w) ans = "unsafe";
    System.out.println(ans);
  }
}