import java.io.*;
import java.util.*;
 
public class Main {
 
 
    public static void main(String[] args) throws Exception {
 
        FastReader fs = new FastReader();
      out = new PrintWriter(new BufferedOutputStream(System.out));
        int n = fs.nextInt();
        int w = fs.nextInt();
        
        if(w>=n){
            out.println("unsafe");
        }else{
            out.println("safe");
        }
 
        out.close();
 
    }
 
    //-----------PrintWriter for faster output---------------------------------
    public static PrintWriter out;
 
    //-----------MyScanner class for faster input----------
    public static class FastReader {
        BufferedReader br;
        StringTokenizer st;
 
        public FastReader() {
            br = new BufferedReader(new InputStreamReader(System.in));
        }
 
        String next() {
            while (st == null || !st.hasMoreElements()) {
                try {
                    st = new StringTokenizer(br.readLine());
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            return st.nextToken();
        }
 
        int nextInt() {
            return Integer.parseInt(next());
        }
 
        long nextLong() {
            return Long.parseLong(next());
        }
 
        double nextDouble() {
            return Double.parseDouble(next());
        }
 
        String nextLine() {
            String str = "";
            try {
                str = br.readLine();
            } catch (IOException e) {
                e.printStackTrace();
            }
            return str;
        }
 
    }
    //--------------------------------------------------------
} import java.io.*; io.* java import java.util.*; util.* java public class Main {
 
 
    public static void main(String[] args) throws Exception {
 
        FastReader fs = new FastReader();
      out = new PrintWriter(new BufferedOutputStream(System.out));
        int n = fs.nextInt();
        int w = fs.nextInt();
        
        if(w>=n){
            out.println("unsafe");
        }else{
            out.println("safe");
        }
 
        out.close();
 
    }
 
    //-----------PrintWriter for faster output---------------------------------
    public static PrintWriter out;
 
    //-----------MyScanner class for faster input----------
    public static class FastReader {
        BufferedReader br;
        StringTokenizer st;
 
        public FastReader() {
            br = new BufferedReader(new InputStreamReader(System.in));
        }
 
        String next() {
            while (st == null || !st.hasMoreElements()) {
                try {
                    st = new StringTokenizer(br.readLine());
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            return st.nextToken();
        }
 
        int nextInt() {
            return Integer.parseInt(next());
        }
 
        long nextLong() {
            return Long.parseLong(next());
        }
 
        double nextDouble() {
            return Double.parseDouble(next());
        }
 
        String nextLine() {
            String str = "";
            try {
                str = br.readLine();
            } catch (IOException e) {
                e.printStackTrace();
            }
            return str;
        }
 
    }
    //--------------------------------------------------------
} Main //-----------PrintWriter for faster output---------------------------------
    public static PrintWriter out; out public static void main(String[] args) throws Exception {
 
        FastReader fs = new FastReader();
      out = new PrintWriter(new BufferedOutputStream(System.out));
        int n = fs.nextInt();
        int w = fs.nextInt();
        
        if(w>=n){
            out.println("unsafe");
        }else{
            out.println("safe");
        }
 
        out.close();
 
    } main {
 
        FastReader fs = new FastReader();
      out = new PrintWriter(new BufferedOutputStream(System.out));
        int n = fs.nextInt();
        int w = fs.nextInt();
        
        if(w>=n){
            out.println("unsafe");
        }else{
            out.println("safe");
        }
 
        out.close();
 
    } FastReader fs = new FastReader(); fs new FastReader() out = new PrintWriter(new BufferedOutputStream(System.out)) out new PrintWriter(new BufferedOutputStream(System.out)) int n = fs.nextInt(); n fs.nextInt() fs.nextInt fs int w = fs.nextInt(); w fs.nextInt() fs.nextInt fs if(w>=n){
            out.println("unsafe");
        }else{
            out.println("safe");
        } w>=n w n {
            out.println("unsafe");
        } out.println("unsafe") out.println out "unsafe" {
            out.println("safe");
        } out.println("safe") out.println out "safe" out.close() out.close out String[] args args public static class FastReader {
        BufferedReader br;
        StringTokenizer st;
 
        public FastReader() {
            br = new BufferedReader(new InputStreamReader(System.in));
        }
 
        String next() {
            while (st == null || !st.hasMoreElements()) {
                try {
                    st = new StringTokenizer(br.readLine());
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            return st.nextToken();
        }
 
        int nextInt() {
            return Integer.parseInt(next());
        }
 
        long nextLong() {
            return Long.parseLong(next());
        }
 
        double nextDouble() {
            return Double.parseDouble(next());
        }
 
        String nextLine() {
            String str = "";
            try {
                str = br.readLine();
            } catch (IOException e) {
                e.printStackTrace();
            }
            return str;
        }
 
    } FastReader BufferedReader br; br StringTokenizer st; st public FastReader() {
            br = new BufferedReader(new InputStreamReader(System.in));
        } FastReader {
            br = new BufferedReader(new InputStreamReader(System.in));
        } br = new BufferedReader(new InputStreamReader(System.in)) br new BufferedReader(new InputStreamReader(System.in)) String next() {
            while (st == null || !st.hasMoreElements()) {
                try {
                    st = new StringTokenizer(br.readLine());
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            return st.nextToken();
        } next {
            while (st == null || !st.hasMoreElements()) {
                try {
                    st = new StringTokenizer(br.readLine());
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            return st.nextToken();
        } while (st == null || !st.hasMoreElements()) {
                try {
                    st = new StringTokenizer(br.readLine());
                } catch (IOException e) {
                    e.printStackTrace();
                }
            } st == null || !st.hasMoreElements() st == null st null !st.hasMoreElements() st.hasMoreElements() st.hasMoreElements st {
                try {
                    st = new StringTokenizer(br.readLine());
                } catch (IOException e) {
                    e.printStackTrace();
                }
            } try {
                    st = new StringTokenizer(br.readLine());
                } catch (IOException e) {
                    e.printStackTrace();
                } catch (IOException e) {
                    e.printStackTrace();
                } IOException e {
                    e.printStackTrace();
                } e.printStackTrace() e.printStackTrace e {
                    st = new StringTokenizer(br.readLine());
                } st = new StringTokenizer(br.readLine()) st new StringTokenizer(br.readLine()) return st.nextToken(); st.nextToken() st.nextToken st int nextInt() {
            return Integer.parseInt(next());
        } nextInt {
            return Integer.parseInt(next());
        } return Integer.parseInt(next()); Integer.parseInt(next()) Integer.parseInt Integer next() next long nextLong() {
            return Long.parseLong(next());
        } nextLong {
            return Long.parseLong(next());
        } return Long.parseLong(next()); Long.parseLong(next()) Long.parseLong Long next() next double nextDouble() {
            return Double.parseDouble(next());
        } nextDouble {
            return Double.parseDouble(next());
        } return Double.parseDouble(next()); Double.parseDouble(next()) Double.parseDouble Double next() next String nextLine() {
            String str = "";
            try {
                str = br.readLine();
            } catch (IOException e) {
                e.printStackTrace();
            }
            return str;
        } nextLine {
            String str = "";
            try {
                str = br.readLine();
            } catch (IOException e) {
                e.printStackTrace();
            }
            return str;
        } String str = ""; str "" try {
                str = br.readLine();
            } catch (IOException e) {
                e.printStackTrace();
            } catch (IOException e) {
                e.printStackTrace();
            } IOException e {
                e.printStackTrace();
            } e.printStackTrace() e.printStackTrace e {
                str = br.readLine();
            } str = br.readLine() str br.readLine() br.readLine br return str; str public class Main {
 
 
    public static void main(String[] args) throws Exception {
 
        FastReader fs = new FastReader();
      out = new PrintWriter(new BufferedOutputStream(System.out));
        int n = fs.nextInt();
        int w = fs.nextInt();
        
        if(w>=n){
            out.println("unsafe");
        }else{
            out.println("safe");
        }
 
        out.close();
 
    }
 
    //-----------PrintWriter for faster output---------------------------------
    public static PrintWriter out;
 
    //-----------MyScanner class for faster input----------
    public static class FastReader {
        BufferedReader br;
        StringTokenizer st;
 
        public FastReader() {
            br = new BufferedReader(new InputStreamReader(System.in));
        }
 
        String next() {
            while (st == null || !st.hasMoreElements()) {
                try {
                    st = new StringTokenizer(br.readLine());
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            return st.nextToken();
        }
 
        int nextInt() {
            return Integer.parseInt(next());
        }
 
        long nextLong() {
            return Long.parseLong(next());
        }
 
        double nextDouble() {
            return Double.parseDouble(next());
        }
 
        String nextLine() {
            String str = "";
            try {
                str = br.readLine();
            } catch (IOException e) {
                e.printStackTrace();
            }
            return str;
        }
 
    }
    //--------------------------------------------------------
} public class Main {
 
 
    public static void main(String[] args) throws Exception {
 
        FastReader fs = new FastReader();
      out = new PrintWriter(new BufferedOutputStream(System.out));
        int n = fs.nextInt();
        int w = fs.nextInt();
        
        if(w>=n){
            out.println("unsafe");
        }else{
            out.println("safe");
        }
 
        out.close();
 
    }
 
    //-----------PrintWriter for faster output---------------------------------
    public static PrintWriter out;
 
    //-----------MyScanner class for faster input----------
    public static class FastReader {
        BufferedReader br;
        StringTokenizer st;
 
        public FastReader() {
            br = new BufferedReader(new InputStreamReader(System.in));
        }
 
        String next() {
            while (st == null || !st.hasMoreElements()) {
                try {
                    st = new StringTokenizer(br.readLine());
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            return st.nextToken();
        }
 
        int nextInt() {
            return Integer.parseInt(next());
        }
 
        long nextLong() {
            return Long.parseLong(next());
        }
 
        double nextDouble() {
            return Double.parseDouble(next());
        }
 
        String nextLine() {
            String str = "";
            try {
                str = br.readLine();
            } catch (IOException e) {
                e.printStackTrace();
            }
            return str;
        }
 
    }
    //--------------------------------------------------------
} Main
import java.io.*;
import java.util.*;
 
public class Main {
 
 
    public static void main(String[] args) throws Exception {
 
        FastReader fs = new FastReader();
      out = new PrintWriter(new BufferedOutputStream(System.out));
        int n = fs.nextInt();
        int w = fs.nextInt();
        
        if(w>=n){
            out.println("unsafe");
        }else{
            out.println("safe");
        }
 
        out.close();
 
    }
 
    //-----------PrintWriter for faster output---------------------------------
    public static PrintWriter out;
 
    //-----------MyScanner class for faster input----------
    public static class FastReader {
        BufferedReader br;
        StringTokenizer st;
 
        public FastReader() {
            br = new BufferedReader(new InputStreamReader(System.in));
        }
 
        String next() {
            while (st == null || !st.hasMoreElements()) {
                try {
                    st = new StringTokenizer(br.readLine());
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            return st.nextToken();
        }
 
        int nextInt() {
            return Integer.parseInt(next());
        }
 
        long nextLong() {
            return Long.parseLong(next());
        }
 
        double nextDouble() {
            return Double.parseDouble(next());
        }
 
        String nextLine() {
            String str = "";
            try {
                str = br.readLine();
            } catch (IOException e) {
                e.printStackTrace();
            }
            return str;
        }
 
    }
    //--------------------------------------------------------
}