import java.io.*;
import java.lang.reflect.Array;
import java.util.*;

public class Main {

    public static void main(String[] args) {

        //r(a, 0, "");
        Scanner in = new Scanner(System.in);
            int N = in.nextInt();
            int W = in.nextInt();
            if(W >= N) {
                System.out.println("unsafe");
            } else {
                System.out.println("safe");
            }

    }

} import java.io.*; io.* java import java.lang.reflect.Array; Array java.lang.reflect import java.util.*; util.* java public class Main {

    public static void main(String[] args) {

        //r(a, 0, "");
        Scanner in = new Scanner(System.in);
            int N = in.nextInt();
            int W = in.nextInt();
            if(W >= N) {
                System.out.println("unsafe");
            } else {
                System.out.println("safe");
            }

    }

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

        //r(a, 0, "");
        Scanner in = new Scanner(System.in);
            int N = in.nextInt();
            int W = in.nextInt();
            if(W >= N) {
                System.out.println("unsafe");
            } else {
                System.out.println("safe");
            }

    } main {

        //r(a, 0, "");
        Scanner in = new Scanner(System.in);
            int N = in.nextInt();
            int W = in.nextInt();
            if(W >= N) {
                System.out.println("unsafe");
            } else {
                System.out.println("safe");
            }

    } Scanner in = new Scanner(System.in); in new Scanner(System.in) int N = in.nextInt(); N in.nextInt() in.nextInt in int W = in.nextInt(); W in.nextInt() in.nextInt in if(W >= N) {
                System.out.println("unsafe");
            } else {
                System.out.println("safe");
            } W >= N W N {
                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) {

        //r(a, 0, "");
        Scanner in = new Scanner(System.in);
            int N = in.nextInt();
            int W = in.nextInt();
            if(W >= N) {
                System.out.println("unsafe");
            } else {
                System.out.println("safe");
            }

    }

} public class Main {

    public static void main(String[] args) {

        //r(a, 0, "");
        Scanner in = new Scanner(System.in);
            int N = in.nextInt();
            int W = in.nextInt();
            if(W >= N) {
                System.out.println("unsafe");
            } else {
                System.out.println("safe");
            }

    }

} Main
import java.io.*;
import java.lang.reflect.Array;
import java.util.*;

public class Main {

    public static void main(String[] args) {

        //r(a, 0, "");
        Scanner in = new Scanner(System.in);
            int N = in.nextInt();
            int W = in.nextInt();
            if(W >= N) {
                System.out.println("unsafe");
            } else {
                System.out.println("safe");
            }

    }

}
