import java.util.Scanner;

public class Main {

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

        String ans = "";
        if (s > w) {
            ans = "safe";
        }
        else {
            ans = "unsafe";
        }
        System.out.println(ans);
    }
} import java.util.Scanner; Scanner 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();

        String ans = "";
        if (s > w) {
            ans = "safe";
        }
        else {
            ans = "unsafe";
        }
        System.out.println(ans);
    }
} Main public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int s = sc.nextInt();
        int w = sc.nextInt();

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

        String ans = "";
        if (s > w) {
            ans = "safe";
        }
        else {
            ans = "unsafe";
        }
        System.out.println(ans);
    } 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 String ans = ""; ans "" if (s > w) {
            ans = "safe";
        }
        else {
            ans = "unsafe";
        } s > w s w {
            ans = "safe";
        } ans = "safe" ans "safe" {
            ans = "unsafe";
        } ans = "unsafe" ans "unsafe" System.out.println(ans) System.out.println System.out System System.out ans 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();

        String ans = "";
        if (s > w) {
            ans = "safe";
        }
        else {
            ans = "unsafe";
        }
        System.out.println(ans);
    }
} public class Main {

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

        String ans = "";
        if (s > w) {
            ans = "safe";
        }
        else {
            ans = "unsafe";
        }
        System.out.println(ans);
    }
} Main
import java.util.Scanner;

public class Main {

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

        String ans = "";
        if (s > w) {
            ans = "safe";
        }
        else {
            ans = "unsafe";
        }
        System.out.println(ans);
    }
}