import java.util.*;

class Main {
    final Scanner sc = new Scanner(System.in);

    public static void main(String[] args) {
        new Main().run();
    }

    private void run() {
        int s = sc.nextInt();
        int w = sc.nextInt();
        System.out.println(s <= w ? "unsafe" : "safe");
    }
} import java.util.*; util.* java class Main {
    final Scanner sc = new Scanner(System.in);

    public static void main(String[] args) {
        new Main().run();
    }

    private void run() {
        int s = sc.nextInt();
        int w = sc.nextInt();
        System.out.println(s <= w ? "unsafe" : "safe");
    }
} Main final Scanner sc = new Scanner(System.in); sc new Scanner(System.in) public static void main(String[] args) {
        new Main().run();
    } main {
        new Main().run();
    } new Main().run() new Main().run new Main() String[] args args private void run() {
        int s = sc.nextInt();
        int w = sc.nextInt();
        System.out.println(s <= w ? "unsafe" : "safe");
    } run {
        int s = sc.nextInt();
        int w = sc.nextInt();
        System.out.println(s <= w ? "unsafe" : "safe");
    } int s = sc.nextInt(); s sc.nextInt() sc.nextInt sc int w = sc.nextInt(); w sc.nextInt() sc.nextInt sc System.out.println(s <= w ? "unsafe" : "safe") System.out.println System.out System System.out s <= w ? "unsafe" : "safe" s <= w s w "unsafe" "safe"
import java.util.*;

class Main {
    final Scanner sc = new Scanner(System.in);

    public static void main(String[] args) {
        new Main().run();
    }

    private void run() {
        int s = sc.nextInt();
        int w = sc.nextInt();
        System.out.println(s <= w ? "unsafe" : "safe");
    }
}
