import java.util.*;
import javax.lang.model.util.ElementScanner6;
//import java.lang.Math;

public class Main {

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

        // 入力
        int s = sc.nextInt();
        int w = sc.nextInt();
        //String s = sc.next();

        // 処理
        String out = "safe";
        if (w >= s) {
            out = "unsafe";
        }

        // 出力
        System.out.println(out);
    }
} import java.util.*; util.* java import javax.lang.model.util.ElementScanner6; ElementScanner6 javax.lang.model.util public class Main {

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

        // 入力
        int s = sc.nextInt();
        int w = sc.nextInt();
        //String s = sc.next();

        // 処理
        String out = "safe";
        if (w >= s) {
            out = "unsafe";
        }

        // 出力
        System.out.println(out);
    }
} Main public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);

        // 入力
        int s = sc.nextInt();
        int w = sc.nextInt();
        //String s = sc.next();

        // 処理
        String out = "safe";
        if (w >= s) {
            out = "unsafe";
        }

        // 出力
        System.out.println(out);
    } main {
        Scanner sc = new Scanner(System.in);

        // 入力
        int s = sc.nextInt();
        int w = sc.nextInt();
        //String s = sc.next();

        // 処理
        String out = "safe";
        if (w >= s) {
            out = "unsafe";
        }

        // 出力
        System.out.println(out);
    } 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 String out = "safe"; out "safe" if (w >= s) {
            out = "unsafe";
        } w >= s w s {
            out = "unsafe";
        } out = "unsafe" out "unsafe" System.out.println(out) System.out.println System.out System System.out out String[] args args public class Main {

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

        // 入力
        int s = sc.nextInt();
        int w = sc.nextInt();
        //String s = sc.next();

        // 処理
        String out = "safe";
        if (w >= s) {
            out = "unsafe";
        }

        // 出力
        System.out.println(out);
    }
} public class Main {

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

        // 入力
        int s = sc.nextInt();
        int w = sc.nextInt();
        //String s = sc.next();

        // 処理
        String out = "safe";
        if (w >= s) {
            out = "unsafe";
        }

        // 出力
        System.out.println(out);
    }
} Main
import java.util.*;
import javax.lang.model.util.ElementScanner6;
//import java.lang.Math;

public class Main {

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

        // 入力
        int s = sc.nextInt();
        int w = sc.nextInt();
        //String s = sc.next();

        // 処理
        String out = "safe";
        if (w >= s) {
            out = "unsafe";
        }

        // 出力
        System.out.println(out);
    }
}