import java.util.*;

public class Main {
    public static void main(String[] args) {
        Main main = new Main();
        main.run();
    }
    
    // 変数一覧
    int s;
    int w;

    public void run() {
        // 入力情報取得
        Scanner sc = new Scanner(System.in);
        s = sc.nextInt();
        w = sc.nextInt();
        sc.close();

        // 解答処理
        solve();
    }
    
    private void solve() {
        if (s<=w) System.out.println("unsafe");
        else System.out.println("safe");
    }
} import java.util.*; util.* java public class Main {
    public static void main(String[] args) {
        Main main = new Main();
        main.run();
    }
    
    // 変数一覧
    int s;
    int w;

    public void run() {
        // 入力情報取得
        Scanner sc = new Scanner(System.in);
        s = sc.nextInt();
        w = sc.nextInt();
        sc.close();

        // 解答処理
        solve();
    }
    
    private void solve() {
        if (s<=w) System.out.println("unsafe");
        else System.out.println("safe");
    }
} Main // 変数一覧
    int s; s int w; w public static void main(String[] args) {
        Main main = new Main();
        main.run();
    } main {
        Main main = new Main();
        main.run();
    } Main main = new Main(); main new Main() main.run() main.run main String[] args args public void run() {
        // 入力情報取得
        Scanner sc = new Scanner(System.in);
        s = sc.nextInt();
        w = sc.nextInt();
        sc.close();

        // 解答処理
        solve();
    } run {
        // 入力情報取得
        Scanner sc = new Scanner(System.in);
        s = sc.nextInt();
        w = sc.nextInt();
        sc.close();

        // 解答処理
        solve();
    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) s = sc.nextInt() s sc.nextInt() sc.nextInt sc w = sc.nextInt() w sc.nextInt() sc.nextInt sc sc.close() sc.close sc solve() solve private void solve() {
        if (s<=w) System.out.println("unsafe");
        else System.out.println("safe");
    } solve {
        if (s<=w) System.out.println("unsafe");
        else System.out.println("safe");
    } if (s<=w) System.out.println("unsafe");
        else System.out.println("safe"); s<=w s w System.out.println("unsafe") System.out.println System.out System System.out "unsafe" System.out.println("safe") System.out.println System.out System System.out "safe" public class Main {
    public static void main(String[] args) {
        Main main = new Main();
        main.run();
    }
    
    // 変数一覧
    int s;
    int w;

    public void run() {
        // 入力情報取得
        Scanner sc = new Scanner(System.in);
        s = sc.nextInt();
        w = sc.nextInt();
        sc.close();

        // 解答処理
        solve();
    }
    
    private void solve() {
        if (s<=w) System.out.println("unsafe");
        else System.out.println("safe");
    }
} public class Main {
    public static void main(String[] args) {
        Main main = new Main();
        main.run();
    }
    
    // 変数一覧
    int s;
    int w;

    public void run() {
        // 入力情報取得
        Scanner sc = new Scanner(System.in);
        s = sc.nextInt();
        w = sc.nextInt();
        sc.close();

        // 解答処理
        solve();
    }
    
    private void solve() {
        if (s<=w) System.out.println("unsafe");
        else System.out.println("safe");
    }
} Main
import java.util.*;

public class Main {
    public static void main(String[] args) {
        Main main = new Main();
        main.run();
    }
    
    // 変数一覧
    int s;
    int w;

    public void run() {
        // 入力情報取得
        Scanner sc = new Scanner(System.in);
        s = sc.nextInt();
        w = sc.nextInt();
        sc.close();

        // 解答処理
        solve();
    }
    
    private void solve() {
        if (s<=w) System.out.println("unsafe");
        else System.out.println("safe");
    }
}