import java.util.*;

public class Main {
    private static final Scanner sc = new Scanner(System.in);

    private void solve() {
        int S = sc.nextInt();
        int W = sc.nextInt();

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

    public static void main(String[] args) {
        new Main().solve();
    }
} import java.util.*; util.* java public class Main {
    private static final Scanner sc = new Scanner(System.in);

    private void solve() {
        int S = sc.nextInt();
        int W = sc.nextInt();

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

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

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

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

    private void solve() {
        int S = sc.nextInt();
        int W = sc.nextInt();

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

    public static void main(String[] args) {
        new Main().solve();
    }
} public class Main {
    private static final Scanner sc = new Scanner(System.in);

    private void solve() {
        int S = sc.nextInt();
        int W = sc.nextInt();

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

    public static void main(String[] args) {
        new Main().solve();
    }
} Main
import java.util.*;

public class Main {
    private static final Scanner sc = new Scanner(System.in);

    private void solve() {
        int S = sc.nextInt();
        int W = sc.nextInt();

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

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