import javax.swing.text.html.HTMLDocument;
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.math.BigInteger;
import java.nio.Buffer;
import java.util.*;

class Main {
    public static void main(String[] args){
        try {
            BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
            String[] ss=br.readLine().split(" ");
            int s=Integer.parseInt(ss[0]);
            int w=Integer.parseInt(ss[1]);
            if(w>=s){
                System.out.println("unsafe");
            }else{
                System.out.println("safe");
            }
        } catch (Exception e) {
            System.out.println("kkkk "+ e.getMessage());
        }
    }
    static void shuffle(int[] a) {
        Random get = new Random();
        for (int i = 0; i < a.length; i++) {
            int r = get.nextInt(a.length);
            int temp = a[i];
            a[i] = a[r];
            a[r] = temp;
        }
    }
} import javax.swing.text.html.HTMLDocument; HTMLDocument javax.swing.text.html import java.io.BufferedReader; BufferedReader java.io import java.io.InputStreamReader; InputStreamReader java.io import java.io.PrintWriter; PrintWriter java.io import java.math.BigInteger; BigInteger java.math import java.nio.Buffer; Buffer java.nio import java.util.*; util.* java class Main {
    public static void main(String[] args){
        try {
            BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
            String[] ss=br.readLine().split(" ");
            int s=Integer.parseInt(ss[0]);
            int w=Integer.parseInt(ss[1]);
            if(w>=s){
                System.out.println("unsafe");
            }else{
                System.out.println("safe");
            }
        } catch (Exception e) {
            System.out.println("kkkk "+ e.getMessage());
        }
    }
    static void shuffle(int[] a) {
        Random get = new Random();
        for (int i = 0; i < a.length; i++) {
            int r = get.nextInt(a.length);
            int temp = a[i];
            a[i] = a[r];
            a[r] = temp;
        }
    }
} Main public static void main(String[] args){
        try {
            BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
            String[] ss=br.readLine().split(" ");
            int s=Integer.parseInt(ss[0]);
            int w=Integer.parseInt(ss[1]);
            if(w>=s){
                System.out.println("unsafe");
            }else{
                System.out.println("safe");
            }
        } catch (Exception e) {
            System.out.println("kkkk "+ e.getMessage());
        }
    } main {
        try {
            BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
            String[] ss=br.readLine().split(" ");
            int s=Integer.parseInt(ss[0]);
            int w=Integer.parseInt(ss[1]);
            if(w>=s){
                System.out.println("unsafe");
            }else{
                System.out.println("safe");
            }
        } catch (Exception e) {
            System.out.println("kkkk "+ e.getMessage());
        }
    } try {
            BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
            String[] ss=br.readLine().split(" ");
            int s=Integer.parseInt(ss[0]);
            int w=Integer.parseInt(ss[1]);
            if(w>=s){
                System.out.println("unsafe");
            }else{
                System.out.println("safe");
            }
        } catch (Exception e) {
            System.out.println("kkkk "+ e.getMessage());
        } catch (Exception e) {
            System.out.println("kkkk "+ e.getMessage());
        } Exception e {
            System.out.println("kkkk "+ e.getMessage());
        } System.out.println("kkkk "+ e.getMessage()) System.out.println System.out System System.out "kkkk "+ e.getMessage() "kkkk " e.getMessage() e.getMessage e {
            BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
            String[] ss=br.readLine().split(" ");
            int s=Integer.parseInt(ss[0]);
            int w=Integer.parseInt(ss[1]);
            if(w>=s){
                System.out.println("unsafe");
            }else{
                System.out.println("safe");
            }
        } BufferedReader br=new BufferedReader(new InputStreamReader(System.in)); br new BufferedReader(new InputStreamReader(System.in)) String[] ss=br.readLine().split(" "); ss br.readLine().split(" ") br.readLine().split br.readLine() br.readLine br " " int s=Integer.parseInt(ss[0]); s Integer.parseInt(ss[0]) Integer.parseInt Integer ss[0] ss 0 int w=Integer.parseInt(ss[1]); w Integer.parseInt(ss[1]) Integer.parseInt Integer ss[1] ss 1 if(w>=s){
                System.out.println("unsafe");
            }else{
                System.out.println("safe");
            } w>=s w s {
                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 static void shuffle(int[] a) {
        Random get = new Random();
        for (int i = 0; i < a.length; i++) {
            int r = get.nextInt(a.length);
            int temp = a[i];
            a[i] = a[r];
            a[r] = temp;
        }
    } shuffle {
        Random get = new Random();
        for (int i = 0; i < a.length; i++) {
            int r = get.nextInt(a.length);
            int temp = a[i];
            a[i] = a[r];
            a[r] = temp;
        }
    } Random get = new Random(); get new Random() for (int i = 0; i < a.length; i++) {
            int r = get.nextInt(a.length);
            int temp = a[i];
            a[i] = a[r];
            a[r] = temp;
        } int i = 0; int i = 0; i 0 i < a.length i a.length a a.length i++ i++ i {
            int r = get.nextInt(a.length);
            int temp = a[i];
            a[i] = a[r];
            a[r] = temp;
        } {
            int r = get.nextInt(a.length);
            int temp = a[i];
            a[i] = a[r];
            a[r] = temp;
        } int r = get.nextInt(a.length); r get.nextInt(a.length) get.nextInt get a.length a a.length int temp = a[i]; temp a[i] a i a[i] = a[r] a[i] a i a[r] a r a[r] = temp a[r] a r temp int[] a a
import javax.swing.text.html.HTMLDocument;
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.math.BigInteger;
import java.nio.Buffer;
import java.util.*;

class Main {
    public static void main(String[] args){
        try {
            BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
            String[] ss=br.readLine().split(" ");
            int s=Integer.parseInt(ss[0]);
            int w=Integer.parseInt(ss[1]);
            if(w>=s){
                System.out.println("unsafe");
            }else{
                System.out.println("safe");
            }
        } catch (Exception e) {
            System.out.println("kkkk "+ e.getMessage());
        }
    }
    static void shuffle(int[] a) {
        Random get = new Random();
        for (int i = 0; i < a.length; i++) {
            int r = get.nextInt(a.length);
            int temp = a[i];
            a[i] = a[r];
            a[r] = temp;
        }
    }
}