import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        new Main().run();
    }

    private void run() {
        Scanner scanner = new Scanner(System.in);
        int S = scanner.nextInt();
        int W = scanner.nextInt();
        if(S <= W) {
            System.out.println("unsafe");
        }else{
            System.out.println("safe");
        }

    }
} import java.util.Scanner; Scanner java.util public class Main {
    public static void main(String[] args) {
        new Main().run();
    }

    private void run() {
        Scanner scanner = new Scanner(System.in);
        int S = scanner.nextInt();
        int W = scanner.nextInt();
        if(S <= W) {
            System.out.println("unsafe");
        }else{
            System.out.println("safe");
        }

    }
} Main public static void main(String[] args) {
        new Main().run();
    } main {
        new Main().run();
    } new Main().run() new Main().run new Main() String[] args args private void run() {
        Scanner scanner = new Scanner(System.in);
        int S = scanner.nextInt();
        int W = scanner.nextInt();
        if(S <= W) {
            System.out.println("unsafe");
        }else{
            System.out.println("safe");
        }

    } run {
        Scanner scanner = new Scanner(System.in);
        int S = scanner.nextInt();
        int W = scanner.nextInt();
        if(S <= W) {
            System.out.println("unsafe");
        }else{
            System.out.println("safe");
        }

    } 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(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" public class Main {
    public static void main(String[] args) {
        new Main().run();
    }

    private void run() {
        Scanner scanner = new Scanner(System.in);
        int S = scanner.nextInt();
        int W = scanner.nextInt();
        if(S <= W) {
            System.out.println("unsafe");
        }else{
            System.out.println("safe");
        }

    }
} public class Main {
    public static void main(String[] args) {
        new Main().run();
    }

    private void run() {
        Scanner scanner = new Scanner(System.in);
        int S = scanner.nextInt();
        int W = scanner.nextInt();
        if(S <= W) {
            System.out.println("unsafe");
        }else{
            System.out.println("safe");
        }

    }
} Main
import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        new Main().run();
    }

    private void run() {
        Scanner scanner = new Scanner(System.in);
        int S = scanner.nextInt();
        int W = scanner.nextInt();
        if(S <= W) {
            System.out.println("unsafe");
        }else{
            System.out.println("safe");
        }

    }
}
