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();
      if(w>=s){
      	System.out.println("unsafe");
      }else{
        System.out.println("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();
      if(w>=s){
      	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){
      	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){
      	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){
      	System.out.println("unsafe");
      }else{
        System.out.println("safe");
      } w>=s w s {
      	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 sc = new Scanner(System.in);
      int s = sc.nextInt();
      int w = sc.nextInt();
      if(w>=s){
      	System.out.println("unsafe");
      }else{
        System.out.println("safe");
      }
    }
} public 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){
      	System.out.println("unsafe");
      }else{
        System.out.println("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();
      if(w>=s){
      	System.out.println("unsafe");
      }else{
        System.out.println("safe");
      }
    }
}
