import java.util.Scanner;

public class Main {
    private static final int MOD = 1_000_000_007;
    private static final String YES = "Yes";
    private static final String NO = "No";

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);

        int S = sc.nextInt();
        int W = sc.nextInt();

        System.out.println(solve(S, W));
    }

    private static String solve(int S, int W) {
        return S <= W ? "unsafe" : "safe";
    }
} import java.util.Scanner; Scanner java.util public class Main {
    private static final int MOD = 1_000_000_007;
    private static final String YES = "Yes";
    private static final String NO = "No";

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);

        int S = sc.nextInt();
        int W = sc.nextInt();

        System.out.println(solve(S, W));
    }

    private static String solve(int S, int W) {
        return S <= W ? "unsafe" : "safe";
    }
} Main private static final int MOD = 1_000_000_007; MOD 1_000_000_007 private static final String YES = "Yes"; YES "Yes" private static final String NO = "No"; NO "No" public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);

        int S = sc.nextInt();
        int W = sc.nextInt();

        System.out.println(solve(S, W));
    } main {
        Scanner sc = new Scanner(System.in);

        int S = sc.nextInt();
        int W = sc.nextInt();

        System.out.println(solve(S, W));
    } 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 System.out.println(solve(S, W)) System.out.println System.out System System.out solve(S, W) solve S W String[] args args private static String solve(int S, int W) {
        return S <= W ? "unsafe" : "safe";
    } solve {
        return S <= W ? "unsafe" : "safe";
    } return S <= W ? "unsafe" : "safe"; S <= W ? "unsafe" : "safe" S <= W S W "unsafe" "safe" int S S int W W public class Main {
    private static final int MOD = 1_000_000_007;
    private static final String YES = "Yes";
    private static final String NO = "No";

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);

        int S = sc.nextInt();
        int W = sc.nextInt();

        System.out.println(solve(S, W));
    }

    private static String solve(int S, int W) {
        return S <= W ? "unsafe" : "safe";
    }
} public class Main {
    private static final int MOD = 1_000_000_007;
    private static final String YES = "Yes";
    private static final String NO = "No";

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);

        int S = sc.nextInt();
        int W = sc.nextInt();

        System.out.println(solve(S, W));
    }

    private static String solve(int S, int W) {
        return S <= W ? "unsafe" : "safe";
    }
} Main
import java.util.Scanner;

public class Main {
    private static final int MOD = 1_000_000_007;
    private static final String YES = "Yes";
    private static final String NO = "No";

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);

        int S = sc.nextInt();
        int W = sc.nextInt();

        System.out.println(solve(S, W));
    }

    private static String solve(int S, int W) {
        return S <= W ? "unsafe" : "safe";
    }
}