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 a = "safe";

        if(w>=s){
            a ="unsafe";
        }

        System.out.print(a);
    }
} 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 a = "safe";

        if(w>=s){
            a ="unsafe";
        }

        System.out.print(a);
    }
} Main public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int s = sc.nextInt();
        int w = sc.nextInt();
        String a = "safe";

        if(w>=s){
            a ="unsafe";
        }

        System.out.print(a);
    } main {
        Scanner sc = new Scanner(System.in);
        int s = sc.nextInt();
        int w = sc.nextInt();
        String a = "safe";

        if(w>=s){
            a ="unsafe";
        }

        System.out.print(a);
    } 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 a = "safe"; a "safe" if(w>=s){
            a ="unsafe";
        } w>=s w s {
            a ="unsafe";
        } a ="unsafe" a "unsafe" System.out.print(a) System.out.print System.out System System.out a 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 a = "safe";

        if(w>=s){
            a ="unsafe";
        }

        System.out.print(a);
    }
} public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int s = sc.nextInt();
        int w = sc.nextInt();
        String a = "safe";

        if(w>=s){
            a ="unsafe";
        }

        System.out.print(a);
    }
} 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 a = "safe";

        if(w>=s){
            a ="unsafe";
        }

        System.out.print(a);
    }
}