import java.util.Scanner;
import java.io.IOException;

public class Main {

    public static void main(String[] args) throws IOException {

        Scanner sc = new Scanner(System.in);
        int s = Integer.parseInt(sc.next());
        int w = Integer.parseInt(sc.next());
        sc.close();
        String result = "safe";
        if (w >= s) {
            result = "unsafe";
        }
        System.out.println(result);
    }
} import java.util.Scanner; Scanner java.util import java.io.IOException; IOException java.io public class Main {

    public static void main(String[] args) throws IOException {

        Scanner sc = new Scanner(System.in);
        int s = Integer.parseInt(sc.next());
        int w = Integer.parseInt(sc.next());
        sc.close();
        String result = "safe";
        if (w >= s) {
            result = "unsafe";
        }
        System.out.println(result);
    }
} Main public static void main(String[] args) throws IOException {

        Scanner sc = new Scanner(System.in);
        int s = Integer.parseInt(sc.next());
        int w = Integer.parseInt(sc.next());
        sc.close();
        String result = "safe";
        if (w >= s) {
            result = "unsafe";
        }
        System.out.println(result);
    } main {

        Scanner sc = new Scanner(System.in);
        int s = Integer.parseInt(sc.next());
        int w = Integer.parseInt(sc.next());
        sc.close();
        String result = "safe";
        if (w >= s) {
            result = "unsafe";
        }
        System.out.println(result);
    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int s = Integer.parseInt(sc.next()); s Integer.parseInt(sc.next()) Integer.parseInt Integer sc.next() sc.next sc int w = Integer.parseInt(sc.next()); w Integer.parseInt(sc.next()) Integer.parseInt Integer sc.next() sc.next sc sc.close() sc.close sc String result = "safe"; result "safe" if (w >= s) {
            result = "unsafe";
        } w >= s w s {
            result = "unsafe";
        } result = "unsafe" result "unsafe" System.out.println(result) System.out.println System.out System System.out result String[] args args public class Main {

    public static void main(String[] args) throws IOException {

        Scanner sc = new Scanner(System.in);
        int s = Integer.parseInt(sc.next());
        int w = Integer.parseInt(sc.next());
        sc.close();
        String result = "safe";
        if (w >= s) {
            result = "unsafe";
        }
        System.out.println(result);
    }
} public class Main {

    public static void main(String[] args) throws IOException {

        Scanner sc = new Scanner(System.in);
        int s = Integer.parseInt(sc.next());
        int w = Integer.parseInt(sc.next());
        sc.close();
        String result = "safe";
        if (w >= s) {
            result = "unsafe";
        }
        System.out.println(result);
    }
} Main
import java.util.Scanner;
import java.io.IOException;

public class Main {

    public static void main(String[] args) throws IOException {

        Scanner sc = new Scanner(System.in);
        int s = Integer.parseInt(sc.next());
        int w = Integer.parseInt(sc.next());
        sc.close();
        String result = "safe";
        if (w >= s) {
            result = "unsafe";
        }
        System.out.println(result);
    }
}
