import java.util.*;

public class Main {

    public static List<List<Integer>> switchList;

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int S = sc.nextInt();
        int W = sc.nextInt();
        sc.close();

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

    }

} import java.util.*; util.* java public class Main {

    public static List<List<Integer>> switchList;

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int S = sc.nextInt();
        int W = sc.nextInt();
        sc.close();

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

    }

} Main public static List<List<Integer>> switchList; switchList public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int S = sc.nextInt();
        int W = sc.nextInt();
        sc.close();

        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();
        sc.close();

        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 sc.close() sc.close 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 List<List<Integer>> switchList;

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int S = sc.nextInt();
        int W = sc.nextInt();
        sc.close();

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

    }

} public class Main {

    public static List<List<Integer>> switchList;

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int S = sc.nextInt();
        int W = sc.nextInt();
        sc.close();

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

    }

} Main
import java.util.*;

public class Main {

    public static List<List<Integer>> switchList;

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int S = sc.nextInt();
        int W = sc.nextInt();
        sc.close();

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

    }

}