import java.util.Scanner;

public class Main {
    public static void main(String args[]){
        Scanner sc = new Scanner(System.in);
        int S = Integer.parseInt(sc.next());
        int W = Integer.parseInt(sc.next());

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

        sc.close();
    }

} import java.util.Scanner; Scanner java.util public class Main {
    public static void main(String args[]){
        Scanner sc = new Scanner(System.in);
        int S = Integer.parseInt(sc.next());
        int W = Integer.parseInt(sc.next());

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

        sc.close();
    }

} Main public static void main(String args[]){
        Scanner sc = new Scanner(System.in);
        int S = Integer.parseInt(sc.next());
        int W = Integer.parseInt(sc.next());

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

        sc.close();
    } main {
        Scanner sc = new Scanner(System.in);
        int S = Integer.parseInt(sc.next());
        int W = Integer.parseInt(sc.next());

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

        sc.close();
    } 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 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" sc.close() sc.close sc String args[] args public class Main {
    public static void main(String args[]){
        Scanner sc = new Scanner(System.in);
        int S = Integer.parseInt(sc.next());
        int W = Integer.parseInt(sc.next());

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

        sc.close();
    }

} public class Main {
    public static void main(String args[]){
        Scanner sc = new Scanner(System.in);
        int S = Integer.parseInt(sc.next());
        int W = Integer.parseInt(sc.next());

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

        sc.close();
    }

} Main
import java.util.Scanner;

public class Main {
    public static void main(String args[]){
        Scanner sc = new Scanner(System.in);
        int S = Integer.parseInt(sc.next());
        int W = Integer.parseInt(sc.next());

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

        sc.close();
    }

}