import java.util.*;

class Main {
    public static void main(String args[]) {
        Scanner inp = new Scanner(System.in);
        do_(inp);
        inp.close();
    }
    public static void do_(Scanner inp) {
        int s = inp.nextInt();
        int w = inp.nextInt();
        System.out.println(w >= s ? "unsafe" : "safe");
    }
} import java.util.*; util.* java class Main {
    public static void main(String args[]) {
        Scanner inp = new Scanner(System.in);
        do_(inp);
        inp.close();
    }
    public static void do_(Scanner inp) {
        int s = inp.nextInt();
        int w = inp.nextInt();
        System.out.println(w >= s ? "unsafe" : "safe");
    }
} Main public static void main(String args[]) {
        Scanner inp = new Scanner(System.in);
        do_(inp);
        inp.close();
    } main {
        Scanner inp = new Scanner(System.in);
        do_(inp);
        inp.close();
    } Scanner inp = new Scanner(System.in); inp new Scanner(System.in) do_(inp) do_ inp inp.close() inp.close inp String args[] args public static void do_(Scanner inp) {
        int s = inp.nextInt();
        int w = inp.nextInt();
        System.out.println(w >= s ? "unsafe" : "safe");
    } do_ {
        int s = inp.nextInt();
        int w = inp.nextInt();
        System.out.println(w >= s ? "unsafe" : "safe");
    } int s = inp.nextInt(); s inp.nextInt() inp.nextInt inp int w = inp.nextInt(); w inp.nextInt() inp.nextInt inp System.out.println(w >= s ? "unsafe" : "safe") System.out.println System.out System System.out w >= s ? "unsafe" : "safe" w >= s w s "unsafe" "safe" Scanner inp inp
import java.util.*;

class Main {
    public static void main(String args[]) {
        Scanner inp = new Scanner(System.in);
        do_(inp);
        inp.close();
    }
    public static void do_(Scanner inp) {
        int s = inp.nextInt();
        int w = inp.nextInt();
        System.out.println(w >= s ? "unsafe" : "safe");
    }
}
