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

class MyScanner {
    BufferedReader br;
    StringTokenizer st;

    public MyScanner() {
        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 PrintWriter out;
    public static void main(String[] args) {
        MyScanner sc = new MyScanner();
        out = new PrintWriter(new BufferedOutputStream(System.out));

        int s = sc.nextInt();
        int w = sc.nextInt();
        if (w>=s){
            out.println("unsafe");
        }else {
            out.println("safe");
        }
        out.close();
    }

} import java.io.*; io.* java import java.util.*; util.* java class MyScanner {
    BufferedReader br;
    StringTokenizer st;

    public MyScanner() {
        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;
    }

} MyScanner BufferedReader br; br StringTokenizer st; st public MyScanner() {
        br = new BufferedReader(new InputStreamReader(System.in));
    } MyScanner {
        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 PrintWriter out;
    public static void main(String[] args) {
        MyScanner sc = new MyScanner();
        out = new PrintWriter(new BufferedOutputStream(System.out));

        int s = sc.nextInt();
        int w = sc.nextInt();
        if (w>=s){
            out.println("unsafe");
        }else {
            out.println("safe");
        }
        out.close();
    }

} Main public static PrintWriter out; out public static void main(String[] args) {
        MyScanner sc = new MyScanner();
        out = new PrintWriter(new BufferedOutputStream(System.out));

        int s = sc.nextInt();
        int w = sc.nextInt();
        if (w>=s){
            out.println("unsafe");
        }else {
            out.println("safe");
        }
        out.close();
    } main {
        MyScanner sc = new MyScanner();
        out = new PrintWriter(new BufferedOutputStream(System.out));

        int s = sc.nextInt();
        int w = sc.nextInt();
        if (w>=s){
            out.println("unsafe");
        }else {
            out.println("safe");
        }
        out.close();
    } MyScanner sc = new MyScanner(); sc new MyScanner() out = new PrintWriter(new BufferedOutputStream(System.out)) out new PrintWriter(new BufferedOutputStream(System.out)) int s = sc.nextInt(); s sc.nextInt() sc.nextInt sc int w = sc.nextInt(); w sc.nextInt() sc.nextInt sc if (w>=s){
            out.println("unsafe");
        }else {
            out.println("safe");
        } w>=s w s {
            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 class Main {

    public static PrintWriter out;
    public static void main(String[] args) {
        MyScanner sc = new MyScanner();
        out = new PrintWriter(new BufferedOutputStream(System.out));

        int s = sc.nextInt();
        int w = sc.nextInt();
        if (w>=s){
            out.println("unsafe");
        }else {
            out.println("safe");
        }
        out.close();
    }

} public class Main {

    public static PrintWriter out;
    public static void main(String[] args) {
        MyScanner sc = new MyScanner();
        out = new PrintWriter(new BufferedOutputStream(System.out));

        int s = sc.nextInt();
        int w = sc.nextInt();
        if (w>=s){
            out.println("unsafe");
        }else {
            out.println("safe");
        }
        out.close();
    }

} Main
import java.io.*;
import java.util.*;

class MyScanner {
    BufferedReader br;
    StringTokenizer st;

    public MyScanner() {
        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 PrintWriter out;
    public static void main(String[] args) {
        MyScanner sc = new MyScanner();
        out = new PrintWriter(new BufferedOutputStream(System.out));

        int s = sc.nextInt();
        int w = sc.nextInt();
        if (w>=s){
            out.println("unsafe");
        }else {
            out.println("safe");
        }
        out.close();
    }

}
