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


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


  }
} Main public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    int S=sc.nextInt();
    int W=sc.nextInt();
  if (W-S>=0) {
    System.out.println("unsafe");
  }else{
    System.out.println("safe");  
  }


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


  }
}
