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