import java.util.Scanner;

public class Main {

    public static void main(String args[]){
        Scanner scanner = new Scanner(System.in);
        int S = scanner.nextInt();
        int W = scanner.nextInt();

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


        scanner.close();
    }

} import java.util.Scanner; Scanner java.util public class Main {

    public static void main(String args[]){
        Scanner scanner = new Scanner(System.in);
        int S = scanner.nextInt();
        int W = scanner.nextInt();

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


        scanner.close();
    }

} Main public static void main(String args[]){
        Scanner scanner = new Scanner(System.in);
        int S = scanner.nextInt();
        int W = scanner.nextInt();

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


        scanner.close();
    } main {
        Scanner scanner = new Scanner(System.in);
        int S = scanner.nextInt();
        int W = scanner.nextInt();

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


        scanner.close();
    } Scanner scanner = new Scanner(System.in); scanner new Scanner(System.in) int S = scanner.nextInt(); S scanner.nextInt() scanner.nextInt scanner int W = scanner.nextInt(); W scanner.nextInt() scanner.nextInt scanner 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" scanner.close() scanner.close scanner String args[] args public class Main {

    public static void main(String args[]){
        Scanner scanner = new Scanner(System.in);
        int S = scanner.nextInt();
        int W = scanner.nextInt();

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


        scanner.close();
    }

} public class Main {

    public static void main(String args[]){
        Scanner scanner = new Scanner(System.in);
        int S = scanner.nextInt();
        int W = scanner.nextInt();

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


        scanner.close();
    }

} Main
import java.util.Scanner;

public class Main {

    public static void main(String args[]){
        Scanner scanner = new Scanner(System.in);
        int S = scanner.nextInt();
        int W = scanner.nextInt();

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


        scanner.close();
    }

}
