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(S<=W){
        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(S<=W){
        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(S<=W){
        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(S<=W){
        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(S<=W){
        System.out.println("unsafe");
      }else{
        System.out.println("safe");
      } S<=W S W {
        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(S<=W){
        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(S<=W){
        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(S<=W){
        System.out.println("unsafe");
      }else{
        System.out.println("safe");
      }
    }
}