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

class Main {
    public static Scan scan = new Scan();
    public static Print print = new Print();

    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));

    public static void main(String[] args) throws Exception {
        int S = scan.scanInt();
        int W = scan.scanInt();
        if (W >= S) {
            print.println("unsafe");
        } else {
            print.println("safe");
        }
        print.close();
    }
}

class Scan {
    private byte[] buf = new byte[1024];
    private int index;
    private InputStream in;
    private int total;

    public Scan() {
        in = System.in;
    }

    public int scan() throws IOException {
        if (total < 0)
            throw new InputMismatchException();
        if (index >= total) {
            index = 0;
            total = in.read(buf);
            if (total <= 0)
                return -1;
        }
        return buf[index++];
    }

    public int scanInt() throws IOException {
        int integer = 0;
        int n = scan();
        while (isWhiteSpace(n))
            n = scan();
        int neg = 1;
        if (n == '-') {
            neg = -1;
            n = scan();
        }
        while (!isWhiteSpace(n)) {
            if (n >= '0' && n <= '9') {
                integer *= 10;
                integer += n - '0';
                n = scan();
            } else
                throw new InputMismatchException();
        }
        return neg * integer;
    }

    public double scanDouble() throws IOException {
        double doub = 0;
        int n = scan();
        while (isWhiteSpace(n))
            n = scan();
        int neg = 1;
        if (n == '-') {
            neg = -1;
            n = scan();
        }
        while (!isWhiteSpace(n) && n != '.') {
            if (n >= '0' && n <= '9') {
                doub *= 10;
                doub += n - '0';
                n = scan();
            } else
                throw new InputMismatchException();
        }
        if (n == '.') {
            n = scan();
            double temp = 1;
            while (!isWhiteSpace(n)) {
                if (n >= '0' && n <= '9') {
                    temp /= 10;
                    doub += (n - '0') * temp;
                    n = scan();
                } else
                    throw new InputMismatchException();
            }
        }
        return doub * neg;
    }

    public String scanString() throws IOException {
        StringBuilder sb = new StringBuilder();
        int n = scan();
        while (isWhiteSpace(n))
            n = scan();
        while (!isWhiteSpace(n)) {
            sb.append((char) n);
            n = scan();
        }
        return sb.toString();
    }

    private boolean isWhiteSpace(int n) {
        if (n == ' ' || n == '\n' || n == '\r' || n == '\t' || n == -1)
            return true;
        return false;
    }
}

class Print {
    private final BufferedWriter bw;

    public Print() {
        this.bw = new BufferedWriter(new OutputStreamWriter(System.out));
    }

    public void print(Object object) throws IOException {
        bw.append("" + object);
    }

    public void println(Object object) throws IOException {
        print(object);
        bw.append("\n");
    }

    public void close() throws IOException {
        bw.close();
    }
} import java.io.*; io.* java import java.util.*; util.* java class Main {
    public static Scan scan = new Scan();
    public static Print print = new Print();

    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));

    public static void main(String[] args) throws Exception {
        int S = scan.scanInt();
        int W = scan.scanInt();
        if (W >= S) {
            print.println("unsafe");
        } else {
            print.println("safe");
        }
        print.close();
    }
} Main public static Scan scan = new Scan(); scan new Scan() public static Print print = new Print(); print new Print() BufferedReader br = new BufferedReader(new InputStreamReader(System.in)); br new BufferedReader(new InputStreamReader(System.in)) public static void main(String[] args) throws Exception {
        int S = scan.scanInt();
        int W = scan.scanInt();
        if (W >= S) {
            print.println("unsafe");
        } else {
            print.println("safe");
        }
        print.close();
    } main {
        int S = scan.scanInt();
        int W = scan.scanInt();
        if (W >= S) {
            print.println("unsafe");
        } else {
            print.println("safe");
        }
        print.close();
    } int S = scan.scanInt(); S scan.scanInt() scan.scanInt scan int W = scan.scanInt(); W scan.scanInt() scan.scanInt scan if (W >= S) {
            print.println("unsafe");
        } else {
            print.println("safe");
        } W >= S W S {
            print.println("unsafe");
        } print.println("unsafe") print.println print "unsafe" {
            print.println("safe");
        } print.println("safe") print.println print "safe" print.close() print.close print String[] args args class Scan {
    private byte[] buf = new byte[1024];
    private int index;
    private InputStream in;
    private int total;

    public Scan() {
        in = System.in;
    }

    public int scan() throws IOException {
        if (total < 0)
            throw new InputMismatchException();
        if (index >= total) {
            index = 0;
            total = in.read(buf);
            if (total <= 0)
                return -1;
        }
        return buf[index++];
    }

    public int scanInt() throws IOException {
        int integer = 0;
        int n = scan();
        while (isWhiteSpace(n))
            n = scan();
        int neg = 1;
        if (n == '-') {
            neg = -1;
            n = scan();
        }
        while (!isWhiteSpace(n)) {
            if (n >= '0' && n <= '9') {
                integer *= 10;
                integer += n - '0';
                n = scan();
            } else
                throw new InputMismatchException();
        }
        return neg * integer;
    }

    public double scanDouble() throws IOException {
        double doub = 0;
        int n = scan();
        while (isWhiteSpace(n))
            n = scan();
        int neg = 1;
        if (n == '-') {
            neg = -1;
            n = scan();
        }
        while (!isWhiteSpace(n) && n != '.') {
            if (n >= '0' && n <= '9') {
                doub *= 10;
                doub += n - '0';
                n = scan();
            } else
                throw new InputMismatchException();
        }
        if (n == '.') {
            n = scan();
            double temp = 1;
            while (!isWhiteSpace(n)) {
                if (n >= '0' && n <= '9') {
                    temp /= 10;
                    doub += (n - '0') * temp;
                    n = scan();
                } else
                    throw new InputMismatchException();
            }
        }
        return doub * neg;
    }

    public String scanString() throws IOException {
        StringBuilder sb = new StringBuilder();
        int n = scan();
        while (isWhiteSpace(n))
            n = scan();
        while (!isWhiteSpace(n)) {
            sb.append((char) n);
            n = scan();
        }
        return sb.toString();
    }

    private boolean isWhiteSpace(int n) {
        if (n == ' ' || n == '\n' || n == '\r' || n == '\t' || n == -1)
            return true;
        return false;
    }
} Scan private byte[] buf = new byte[1024]; buf new byte[1024] 1024 private int index; index private InputStream in; in private int total; total public Scan() {
        in = System.in;
    } Scan {
        in = System.in;
    } in = System.in in System.in System System.in public int scan() throws IOException {
        if (total < 0)
            throw new InputMismatchException();
        if (index >= total) {
            index = 0;
            total = in.read(buf);
            if (total <= 0)
                return -1;
        }
        return buf[index++];
    } scan {
        if (total < 0)
            throw new InputMismatchException();
        if (index >= total) {
            index = 0;
            total = in.read(buf);
            if (total <= 0)
                return -1;
        }
        return buf[index++];
    } if (total < 0)
            throw new InputMismatchException(); total < 0 total 0 throw new InputMismatchException(); new InputMismatchException() if (index >= total) {
            index = 0;
            total = in.read(buf);
            if (total <= 0)
                return -1;
        } index >= total index total {
            index = 0;
            total = in.read(buf);
            if (total <= 0)
                return -1;
        } index = 0 index 0 total = in.read(buf) total in.read(buf) in.read in buf if (total <= 0)
                return -1; total <= 0 total 0 return -1; -1 1 return buf[index++]; buf[index++] buf index++ index public int scanInt() throws IOException {
        int integer = 0;
        int n = scan();
        while (isWhiteSpace(n))
            n = scan();
        int neg = 1;
        if (n == '-') {
            neg = -1;
            n = scan();
        }
        while (!isWhiteSpace(n)) {
            if (n >= '0' && n <= '9') {
                integer *= 10;
                integer += n - '0';
                n = scan();
            } else
                throw new InputMismatchException();
        }
        return neg * integer;
    } scanInt {
        int integer = 0;
        int n = scan();
        while (isWhiteSpace(n))
            n = scan();
        int neg = 1;
        if (n == '-') {
            neg = -1;
            n = scan();
        }
        while (!isWhiteSpace(n)) {
            if (n >= '0' && n <= '9') {
                integer *= 10;
                integer += n - '0';
                n = scan();
            } else
                throw new InputMismatchException();
        }
        return neg * integer;
    } int integer = 0; integer 0 int n = scan(); n scan() scan while (isWhiteSpace(n))
            n = scan(); isWhiteSpace(n) isWhiteSpace n n = scan() n scan() scan int neg = 1; neg 1 if (n == '-') {
            neg = -1;
            n = scan();
        } n == '-' n '-' {
            neg = -1;
            n = scan();
        } neg = -1 neg -1 1 n = scan() n scan() scan while (!isWhiteSpace(n)) {
            if (n >= '0' && n <= '9') {
                integer *= 10;
                integer += n - '0';
                n = scan();
            } else
                throw new InputMismatchException();
        } !isWhiteSpace(n) isWhiteSpace(n) isWhiteSpace n {
            if (n >= '0' && n <= '9') {
                integer *= 10;
                integer += n - '0';
                n = scan();
            } else
                throw new InputMismatchException();
        } if (n >= '0' && n <= '9') {
                integer *= 10;
                integer += n - '0';
                n = scan();
            } else
                throw new InputMismatchException(); n >= '0' && n <= '9' n >= '0' n '0' n <= '9' n '9' {
                integer *= 10;
                integer += n - '0';
                n = scan();
            } integer *= 10 integer 10 integer += n - '0' integer n - '0' n '0' n = scan() n scan() scan throw new InputMismatchException(); new InputMismatchException() return neg * integer; neg * integer neg integer public double scanDouble() throws IOException {
        double doub = 0;
        int n = scan();
        while (isWhiteSpace(n))
            n = scan();
        int neg = 1;
        if (n == '-') {
            neg = -1;
            n = scan();
        }
        while (!isWhiteSpace(n) && n != '.') {
            if (n >= '0' && n <= '9') {
                doub *= 10;
                doub += n - '0';
                n = scan();
            } else
                throw new InputMismatchException();
        }
        if (n == '.') {
            n = scan();
            double temp = 1;
            while (!isWhiteSpace(n)) {
                if (n >= '0' && n <= '9') {
                    temp /= 10;
                    doub += (n - '0') * temp;
                    n = scan();
                } else
                    throw new InputMismatchException();
            }
        }
        return doub * neg;
    } scanDouble {
        double doub = 0;
        int n = scan();
        while (isWhiteSpace(n))
            n = scan();
        int neg = 1;
        if (n == '-') {
            neg = -1;
            n = scan();
        }
        while (!isWhiteSpace(n) && n != '.') {
            if (n >= '0' && n <= '9') {
                doub *= 10;
                doub += n - '0';
                n = scan();
            } else
                throw new InputMismatchException();
        }
        if (n == '.') {
            n = scan();
            double temp = 1;
            while (!isWhiteSpace(n)) {
                if (n >= '0' && n <= '9') {
                    temp /= 10;
                    doub += (n - '0') * temp;
                    n = scan();
                } else
                    throw new InputMismatchException();
            }
        }
        return doub * neg;
    } double doub = 0; doub 0 int n = scan(); n scan() scan while (isWhiteSpace(n))
            n = scan(); isWhiteSpace(n) isWhiteSpace n n = scan() n scan() scan int neg = 1; neg 1 if (n == '-') {
            neg = -1;
            n = scan();
        } n == '-' n '-' {
            neg = -1;
            n = scan();
        } neg = -1 neg -1 1 n = scan() n scan() scan while (!isWhiteSpace(n) && n != '.') {
            if (n >= '0' && n <= '9') {
                doub *= 10;
                doub += n - '0';
                n = scan();
            } else
                throw new InputMismatchException();
        } !isWhiteSpace(n) && n != '.' !isWhiteSpace(n) isWhiteSpace(n) isWhiteSpace n n != '.' n '.' {
            if (n >= '0' && n <= '9') {
                doub *= 10;
                doub += n - '0';
                n = scan();
            } else
                throw new InputMismatchException();
        } if (n >= '0' && n <= '9') {
                doub *= 10;
                doub += n - '0';
                n = scan();
            } else
                throw new InputMismatchException(); n >= '0' && n <= '9' n >= '0' n '0' n <= '9' n '9' {
                doub *= 10;
                doub += n - '0';
                n = scan();
            } doub *= 10 doub 10 doub += n - '0' doub n - '0' n '0' n = scan() n scan() scan throw new InputMismatchException(); new InputMismatchException() if (n == '.') {
            n = scan();
            double temp = 1;
            while (!isWhiteSpace(n)) {
                if (n >= '0' && n <= '9') {
                    temp /= 10;
                    doub += (n - '0') * temp;
                    n = scan();
                } else
                    throw new InputMismatchException();
            }
        } n == '.' n '.' {
            n = scan();
            double temp = 1;
            while (!isWhiteSpace(n)) {
                if (n >= '0' && n <= '9') {
                    temp /= 10;
                    doub += (n - '0') * temp;
                    n = scan();
                } else
                    throw new InputMismatchException();
            }
        } n = scan() n scan() scan double temp = 1; temp 1 while (!isWhiteSpace(n)) {
                if (n >= '0' && n <= '9') {
                    temp /= 10;
                    doub += (n - '0') * temp;
                    n = scan();
                } else
                    throw new InputMismatchException();
            } !isWhiteSpace(n) isWhiteSpace(n) isWhiteSpace n {
                if (n >= '0' && n <= '9') {
                    temp /= 10;
                    doub += (n - '0') * temp;
                    n = scan();
                } else
                    throw new InputMismatchException();
            } if (n >= '0' && n <= '9') {
                    temp /= 10;
                    doub += (n - '0') * temp;
                    n = scan();
                } else
                    throw new InputMismatchException(); n >= '0' && n <= '9' n >= '0' n '0' n <= '9' n '9' {
                    temp /= 10;
                    doub += (n - '0') * temp;
                    n = scan();
                } temp /= 10 temp 10 doub += (n - '0') * temp doub (n - '0') * temp (n - '0') n '0' temp n = scan() n scan() scan throw new InputMismatchException(); new InputMismatchException() return doub * neg; doub * neg doub neg public String scanString() throws IOException {
        StringBuilder sb = new StringBuilder();
        int n = scan();
        while (isWhiteSpace(n))
            n = scan();
        while (!isWhiteSpace(n)) {
            sb.append((char) n);
            n = scan();
        }
        return sb.toString();
    } scanString {
        StringBuilder sb = new StringBuilder();
        int n = scan();
        while (isWhiteSpace(n))
            n = scan();
        while (!isWhiteSpace(n)) {
            sb.append((char) n);
            n = scan();
        }
        return sb.toString();
    } StringBuilder sb = new StringBuilder(); sb new StringBuilder() int n = scan(); n scan() scan while (isWhiteSpace(n))
            n = scan(); isWhiteSpace(n) isWhiteSpace n n = scan() n scan() scan while (!isWhiteSpace(n)) {
            sb.append((char) n);
            n = scan();
        } !isWhiteSpace(n) isWhiteSpace(n) isWhiteSpace n {
            sb.append((char) n);
            n = scan();
        } sb.append((char) n) sb.append sb (char) n n = scan() n scan() scan return sb.toString(); sb.toString() sb.toString sb private boolean isWhiteSpace(int n) {
        if (n == ' ' || n == '\n' || n == '\r' || n == '\t' || n == -1)
            return true;
        return false;
    } isWhiteSpace {
        if (n == ' ' || n == '\n' || n == '\r' || n == '\t' || n == -1)
            return true;
        return false;
    } if (n == ' ' || n == '\n' || n == '\r' || n == '\t' || n == -1)
            return true; n == ' ' || n == '\n' || n == '\r' || n == '\t' || n == -1 n == '\t' n == '\r' n == ' ' || n == '\n' || n == '\r' || n == '\t' || n == -1 n == ' ' n ' ' n == '\n' n '\n' n == '\r' n '\r' n == '\t' n '\t' n == -1 n -1 1 return true; true return false; false int n n class Print {
    private final BufferedWriter bw;

    public Print() {
        this.bw = new BufferedWriter(new OutputStreamWriter(System.out));
    }

    public void print(Object object) throws IOException {
        bw.append("" + object);
    }

    public void println(Object object) throws IOException {
        print(object);
        bw.append("\n");
    }

    public void close() throws IOException {
        bw.close();
    }
} Print private final BufferedWriter bw; bw public Print() {
        this.bw = new BufferedWriter(new OutputStreamWriter(System.out));
    } Print {
        this.bw = new BufferedWriter(new OutputStreamWriter(System.out));
    } this.bw = new BufferedWriter(new OutputStreamWriter(System.out)) this.bw this this.bw new BufferedWriter(new OutputStreamWriter(System.out)) public void print(Object object) throws IOException {
        bw.append("" + object);
    } print {
        bw.append("" + object);
    } bw.append("" + object) bw.append bw "" + object "" object Object object object public void println(Object object) throws IOException {
        print(object);
        bw.append("\n");
    } println {
        print(object);
        bw.append("\n");
    } print(object) print object bw.append("\n") bw.append bw "\n" Object object object public void close() throws IOException {
        bw.close();
    } close {
        bw.close();
    } bw.close() bw.close bw
import java.io.*;
import java.util.*;

class Main {
    public static Scan scan = new Scan();
    public static Print print = new Print();

    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));

    public static void main(String[] args) throws Exception {
        int S = scan.scanInt();
        int W = scan.scanInt();
        if (W >= S) {
            print.println("unsafe");
        } else {
            print.println("safe");
        }
        print.close();
    }
}

class Scan {
    private byte[] buf = new byte[1024];
    private int index;
    private InputStream in;
    private int total;

    public Scan() {
        in = System.in;
    }

    public int scan() throws IOException {
        if (total < 0)
            throw new InputMismatchException();
        if (index >= total) {
            index = 0;
            total = in.read(buf);
            if (total <= 0)
                return -1;
        }
        return buf[index++];
    }

    public int scanInt() throws IOException {
        int integer = 0;
        int n = scan();
        while (isWhiteSpace(n))
            n = scan();
        int neg = 1;
        if (n == '-') {
            neg = -1;
            n = scan();
        }
        while (!isWhiteSpace(n)) {
            if (n >= '0' && n <= '9') {
                integer *= 10;
                integer += n - '0';
                n = scan();
            } else
                throw new InputMismatchException();
        }
        return neg * integer;
    }

    public double scanDouble() throws IOException {
        double doub = 0;
        int n = scan();
        while (isWhiteSpace(n))
            n = scan();
        int neg = 1;
        if (n == '-') {
            neg = -1;
            n = scan();
        }
        while (!isWhiteSpace(n) && n != '.') {
            if (n >= '0' && n <= '9') {
                doub *= 10;
                doub += n - '0';
                n = scan();
            } else
                throw new InputMismatchException();
        }
        if (n == '.') {
            n = scan();
            double temp = 1;
            while (!isWhiteSpace(n)) {
                if (n >= '0' && n <= '9') {
                    temp /= 10;
                    doub += (n - '0') * temp;
                    n = scan();
                } else
                    throw new InputMismatchException();
            }
        }
        return doub * neg;
    }

    public String scanString() throws IOException {
        StringBuilder sb = new StringBuilder();
        int n = scan();
        while (isWhiteSpace(n))
            n = scan();
        while (!isWhiteSpace(n)) {
            sb.append((char) n);
            n = scan();
        }
        return sb.toString();
    }

    private boolean isWhiteSpace(int n) {
        if (n == ' ' || n == '\n' || n == '\r' || n == '\t' || n == -1)
            return true;
        return false;
    }
}

class Print {
    private final BufferedWriter bw;

    public Print() {
        this.bw = new BufferedWriter(new OutputStreamWriter(System.out));
    }

    public void print(Object object) throws IOException {
        bw.append("" + object);
    }

    public void println(Object object) throws IOException {
        print(object);
        bw.append("\n");
    }

    public void close() throws IOException {
        bw.close();
    }
}