import java.util.HashMap;
import java.util.Map;
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();
        sc.close();
        if(s<=w){
            System.out.println("unsafe");

        }else{
            System.out.println("safe");
        }
    }
} import java.util.HashMap; HashMap java.util import java.util.Map; Map java.util 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();
        sc.close();
        if(s<=w){
            System.out.println("unsafe");

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

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

        }else{
            System.out.println("safe");
        }
    } 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 sc.close() sc.close sc if(s<=w){
            System.out.println("unsafe");

        }else{
            System.out.println("safe");
        } s<=w s w {
            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" 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();
        sc.close();
        if(s<=w){
            System.out.println("unsafe");

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

        }else{
            System.out.println("safe");
        }
    }
} Main
import java.util.HashMap;
import java.util.Map;
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();
        sc.close();
        if(s<=w){
            System.out.println("unsafe");

        }else{
            System.out.println("safe");
        }
    }
}