
import java.util.*;
import java.io.*;

import static java.lang.Character.isUpperCase;

public class Main {

    public static void main(String[] args) {

        Scanner in = new Scanner(System.in);


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

        if(S<=W)
        {
            System.out.println("unsafe");
        }

        else
            {
                System.out.println("safe");
            }
 }

    }







 import java.util.*; util.* java import java.io.*; io.* java import static java.lang.Character.isUpperCase; import static java.lang.Character.isUpperCase; import static java.lang.Character.isUpperCase; public class Main {

    public static void main(String[] args) {

        Scanner in = new Scanner(System.in);


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

        if(S<=W)
        {
            System.out.println("unsafe");
        }

        else
            {
                System.out.println("safe");
            }
 }

    } Main public static void main(String[] args) {

        Scanner in = new Scanner(System.in);


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

        if(S<=W)
        {
            System.out.println("unsafe");
        }

        else
            {
                System.out.println("safe");
            }
 } main {

        Scanner in = new Scanner(System.in);


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

        if(S<=W)
        {
            System.out.println("unsafe");
        }

        else
            {
                System.out.println("safe");
            }
 } Scanner in = new Scanner(System.in); in new Scanner(System.in) int S  =  in.nextInt(); S in.nextInt() in.nextInt in int W =   in.nextInt(); W in.nextInt() in.nextInt in 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" String[] args args public class Main {

    public static void main(String[] args) {

        Scanner in = new Scanner(System.in);


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

        if(S<=W)
        {
            System.out.println("unsafe");
        }

        else
            {
                System.out.println("safe");
            }
 }

    } public class Main {

    public static void main(String[] args) {

        Scanner in = new Scanner(System.in);


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

        if(S<=W)
        {
            System.out.println("unsafe");
        }

        else
            {
                System.out.println("safe");
            }
 }

    } Main

import java.util.*;
import java.io.*;

import static java.lang.Character.isUpperCase;

public class Main {

    public static void main(String[] args) {

        Scanner in = new Scanner(System.in);


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

        if(S<=W)
        {
            System.out.println("unsafe");
        }

        else
            {
                System.out.println("safe");
            }
 }

    }








