import java.io.InputStream;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.OptionalInt;
import java.util.function.IntUnaryOperator;
import java.util.function.LongUnaryOperator;


public class Main {
    public static void main(String[] args) throws Exception {
        ExtendedScanner sc = new ExtendedScanner();
        FastPrintStream pw = new FastPrintStream();
        solve(sc, pw);
        sc.close();
        pw.flush();
        pw.close();
    }

    public static void solve(ExtendedScanner sc, FastPrintStream pw) {
        int k = sc.nextInt();
        int n = sc.nextInt();
        var sieve = new LinearSieve(n);
        int[] primes = sieve.primes();
        int num = sieve.primeNum();
        int idx = 0;
        while (primes[idx] < k) idx++;
        primes = Arrays.copyOfRange(primes, idx, num);

        int[] cnt = new int[10];
        int m = primes.length;
        int[] hash = new int[m];
        int max = 0;
        int maxl = 0;
        int i = 0;
        for (int j = 0; j < m; j++) {
            int x = hash[j] = hash(primes[j]);
            if (++cnt[x] > 1) {
                while (true) {
                    int y = hash[i++];
                    --cnt[y];
                    if (y == x) break;
                }
            }
            int l = j - i + 1;
            if (max <= l) {
                max = l;
                maxl = primes[i];
            }
        }
        pw.println(maxl);
    }

    static int hash(int x) {
        while (x >= 10) {
            int hash = 0;
            while (x > 0) {
                hash += x % 10;
                x /= 10;
            }
            x = hash;
        }
        return x;
    }
}

/**
 * @author https://atcoder.jp/users/suisen
 */
class FastScanner implements AutoCloseable {
    private final ByteBuffer tokenBuf = new ByteBuffer();
    private final java.io.InputStream in;
    private final byte[] rawBuf = new byte[1 << 14];
    private int ptr = 0;
    private int buflen = 0;

    public FastScanner(java.io.InputStream in) {
        this.in = in;
    }

    public FastScanner() {
        this(new java.io.FileInputStream(java.io.FileDescriptor.in));
    }

    private final int readByte() {
        if (ptr < buflen) return rawBuf[ptr++];
        ptr = 0;
        try {
            buflen = in.read(rawBuf);
            if (buflen > 0) {
                return rawBuf[ptr++];
            } else {
                throw new java.io.EOFException();
            }
        } catch (java.io.IOException e) {
            throw new java.io.UncheckedIOException(e);
        }
    }

    private final int readByteUnsafe() {
        if (ptr < buflen) return rawBuf[ptr++];
        ptr = 0;
        try {
            buflen = in.read(rawBuf);
            if (buflen > 0) {
                return rawBuf[ptr++];
            } else {
                return -1;
            }
        } catch (java.io.IOException e) {
            throw new java.io.UncheckedIOException(e);
        }
    }

    private final int skipUnprintableChars() {
        int b = readByte();
        while (b <= 32 || b >= 127) b = readByte();
        return b;
    }

    private final void loadToken() {
        tokenBuf.clear();
        for (int b = skipUnprintableChars(); 32 < b && b < 127; b = readByteUnsafe()) {
            tokenBuf.append(b);
        }
    }

    public final boolean hasNext() {
        for (int b = readByteUnsafe(); b <= 32 || b >= 127; b = readByteUnsafe()) {
            if (b == -1) return false;
        }
        --ptr;
        return true;
    }

    public final String next() {
        loadToken();
        return new String(tokenBuf.getRawBuf(), 0, tokenBuf.size());
    }

    public final String nextLine() {
        tokenBuf.clear();
        for (int b = readByte(); b != '\n'; b = readByteUnsafe()) {
            if (b == -1) break;
            tokenBuf.append(b);
        }
        return new String(tokenBuf.getRawBuf(), 0, tokenBuf.size());
    }

    public final char nextChar() {
        return (char) skipUnprintableChars();
    }

    public final char[] nextChars() {
        loadToken();
        return tokenBuf.toCharArray();
    }

    public final long nextLong() {
        long n = 0;
        boolean isNegative = false;
        int b = skipUnprintableChars();
        if (b == '-') {
            isNegative = true;
            b = readByteUnsafe();
        }
        if (b < '0' || '9' < b) throw new NumberFormatException();
        while ('0' <= b && b <= '9') {
            // -9223372036854775808 - 9223372036854775807
            if (n >= 922337203685477580l) {
                if (n > 922337203685477580l) {
                    throw new ArithmeticException("long overflow");
                }
                if (isNegative) {
                    if (b >= '9') {
                        throw new ArithmeticException("long overflow");
                    }
                    n = -n - (b + '0');
                    b = readByteUnsafe();
                    if ('0' <= b && b <= '9') {
                        throw new ArithmeticException("long overflow");
                    } else if (b <= 32 || b >= 127) {
                        return n;
                    } else {
                        throw new NumberFormatException();
                    }
                } else {
                    if (b >= '8') {
                        throw new ArithmeticException("long overflow");
                    }
                    n = n * 10 + b - '0';
                    b = readByteUnsafe();
                    if ('0' <= b && b <= '9') {
                        throw new ArithmeticException("long overflow");
                    } else if (b <= 32 || b >= 127) {
                        return n;
                    } else {
                        throw new NumberFormatException();
                    }
                }
            }
            n = n * 10 + b - '0';
            b = readByteUnsafe();
        }
        if (b <= 32 || b >= 127) return isNegative ? -n : n;
        throw new NumberFormatException();
    }
    public final int nextInt() {
        long value = nextLong();
        if ((int) value != value) {
            throw new ArithmeticException("int overflow");
        }
        return (int) value;
    }
    public final double nextDouble() {
        return Double.parseDouble(next());
    }
    public final void close() {
        try {
            in.close();
        } catch (java.io.IOException e) {
            throw new java.io.UncheckedIOException(e);
        }
    }

    private static final class ByteBuffer {
        private static final int DEFAULT_BUF_SIZE = 1 << 12;
        private byte[] buf;
        private int ptr = 0;
        private ByteBuffer(int capacity) {
            this.buf = new byte[capacity];
        }
        private ByteBuffer() {
            this(DEFAULT_BUF_SIZE);
        }
        private ByteBuffer append(int b) {
            if (ptr == buf.length) {
                int newLength = buf.length << 1;
                byte[] newBuf = new byte[newLength];
                System.arraycopy(buf, 0, newBuf, 0, buf.length);
                buf = newBuf;
            }
            buf[ptr++] = (byte) b;
            return this;
        }
        private char[] toCharArray() {
            char[] chs = new char[ptr];
            for (int i = 0; i < ptr; i++) {
                chs[i] = (char) buf[i];
            }
            return chs;
        }
        private byte[] getRawBuf() {
            return buf;
        }
        private int size() {
            return ptr;
        }
        private void clear() {
            ptr = 0;
        }
    }
}


/**
 * @author https://atcoder.jp/users/suisen
 */
final class ExtendedScanner extends FastScanner {
    public ExtendedScanner() {super();}
    public ExtendedScanner(InputStream in) {super(in);}
    public int[] ints(final int n) {
        final int[] a = new int[n];
        Arrays.setAll(a, $ -> nextInt());
        return a;
    }
    public int[] ints(final int n, final IntUnaryOperator f) {
        final int[] a = new int[n];
        Arrays.setAll(a, $ -> f.applyAsInt(nextInt()));
        return a;
    }
    public int[][] ints(final int n, final int m) {
        final int[][] a = new int[n][];
        Arrays.setAll(a, $ -> ints(m));
        return a;
    }
    public int[][] ints(final int n, final int m, final IntUnaryOperator f) {
        final int[][] a = new int[n][];
        Arrays.setAll(a, $ -> ints(m, f));
        return a;
    }
    public long[] longs(final int n) {
        final long[] a = new long[n];
        Arrays.setAll(a, $ -> nextLong());
        return a;
    }
    public long[] longs(final int n, final LongUnaryOperator f) {
        final long[] a = new long[n];
        Arrays.setAll(a, $ -> f.applyAsLong(nextLong()));
        return a;
    }
    public long[][] longs(final int n, final int m) {
        final long[][] a = new long[n][];
        Arrays.setAll(a, $ -> longs(m));
        return a;
    }
    public long[][] longs(final int n, final int m, final LongUnaryOperator f) {
        final long[][] a = new long[n][];
        Arrays.setAll(a, $ -> longs(m, f));
        return a;
    }
    public char[][] charArrays(final int n) {
        final char[][] c = new char[n][];
        Arrays.setAll(c, $ -> nextChars());
        return c;
    }
    public double[] doubles(final int n) {
        final double[] a = new double[n];
        Arrays.setAll(a, $ -> nextDouble());
        return a;
    }
    public double[][] doubles(final int n, final int m) {
        final double[][] a = new double[n][];
        Arrays.setAll(a, $ -> doubles(m));
        return a;
    }
    public String[] strings(final int n) {
        final String[] s = new String[n];
        Arrays.setAll(s, $ -> next());
        return s;
    }
}

class IntPrimePower {
    public final int prime, index;
    IntPrimePower(int prime, int index) {
        this.prime = prime;
        this.index = index;
    }
}

/**
 * @author https://atcoder.jp/users/suisen
 */
class FastPrintStream implements AutoCloseable {
    private static final int INT_MAX_LEN = 11;
    private static final int LONG_MAX_LEN = 20;

    private int precision = 9;

    private static final int BUF_SIZE = 1 << 14;
    private static final int BUF_SIZE_MINUS_INT_MAX_LEN = BUF_SIZE - INT_MAX_LEN;
    private static final int BUF_SIZE_MINUS_LONG_MAX_LEN = BUF_SIZE - LONG_MAX_LEN;
    private final byte[] buf = new byte[BUF_SIZE];
    private int ptr = 0;
    private final java.lang.reflect.Field strField;
    private final java.nio.charset.CharsetEncoder encoder;

    private final java.io.OutputStream out;

    public FastPrintStream(java.io.OutputStream out) {
        this.out = out;
        java.lang.reflect.Field f;
        try {
            f = java.lang.String.class.getDeclaredField("value");
            f.setAccessible(true);
        } catch (NoSuchFieldException | SecurityException e) {
            f = null;
        }
        this.strField = f;
        this.encoder = java.nio.charset.StandardCharsets.US_ASCII.newEncoder();
    }

    public FastPrintStream(java.io.File file) throws java.io.IOException {
        this(new java.io.FileOutputStream(file));
    }

    public FastPrintStream(java.lang.String filename) throws java.io.IOException {
        this(new java.io.File(filename));
    }

    public FastPrintStream() {
        this(new java.io.FileOutputStream(java.io.FileDescriptor.out));
    }

    public FastPrintStream println() {
        if (ptr == BUF_SIZE) internalFlush();
        buf[ptr++] = (byte) '\n';
        return this;
    }

    public FastPrintStream println(java.lang.Object o) {
        return print(o).println();
    }

    public FastPrintStream println(java.lang.String s) {
        return print(s).println();
    }

    public FastPrintStream println(char[] s) {
        return print(s).println();
    }

    public FastPrintStream println(char c) {
        return print(c).println();
    }

    public FastPrintStream println(int x) {
        return print(x).println();
    }

    public FastPrintStream println(long x) {
        return print(x).println();
    }

    public FastPrintStream println(double d, int precision) {
        return print(d, precision).println();
    }

    public FastPrintStream println(double d) {
        return print(d).println();
    }

    private FastPrintStream print(byte[] bytes) {
        int n = bytes.length;
        if (ptr + n > BUF_SIZE) {
            internalFlush();
            try {
                out.write(bytes);
            } catch (java.io.IOException e) {
                throw new java.io.UncheckedIOException(e);
            }
        } else {
            System.arraycopy(bytes, 0, buf, ptr, n);
            ptr += n;
        }
        return this;
    }

    public FastPrintStream print(java.lang.Object o) {
        return print(o.toString());
    }

    public FastPrintStream print(java.lang.String s) {
        if (strField == null) {
            return print(s.getBytes());
        } else {
            try {
                Object value = strField.get(s);
                if (value instanceof byte[]) {
                    return print((byte[]) value);
                } else {
                    return print((char[]) value);
                }
            } catch (IllegalAccessException e) {
                return print(s.getBytes());
            }
        }
    }

    public FastPrintStream print(char[] s) {
        try {
            return print(encoder.encode(java.nio.CharBuffer.wrap(s)).array());
        } catch (java.nio.charset.CharacterCodingException e) {
            byte[] bytes = new byte[s.length];
            for (int i = 0; i < s.length; i++) {
                bytes[i] = (byte) s[i];
            }
            return print(bytes);
        }
    }

    public FastPrintStream print(char c) {
        if (ptr == BUF_SIZE) internalFlush();
        buf[ptr++] = (byte) c;
        return this;
    }

    public FastPrintStream print(int x) {
        if (ptr > BUF_SIZE_MINUS_INT_MAX_LEN) internalFlush();
        if (-10 < x && x < 10) {
            if (x < 0) {
                buf[ptr++] = '-';
                x = -x;
            }
            buf[ptr++] = (byte) ('0' + x);
            return this;
        }
        int d;
        if (x < 0) {
            if (x == Integer.MIN_VALUE) {
                buf[ptr++] = '-'; buf[ptr++] = '2'; buf[ptr++] = '1'; buf[ptr++] = '4';
                buf[ptr++] = '7'; buf[ptr++] = '4'; buf[ptr++] = '8'; buf[ptr++] = '3';
                buf[ptr++] = '6'; buf[ptr++] = '4'; buf[ptr++] = '8';
                return this;
            }
            d = len(x = -x);
            buf[ptr++] = '-';
        } else {
            d = len(x);
        }
        int j = ptr += d; 
        while (x > 0) {
            buf[--j] = (byte) ('0' + (x % 10));
            x /= 10;
        }
        return this;
    }

    public FastPrintStream print(long x) {
        if ((int) x == x) return print((int) x);
        if (ptr > BUF_SIZE_MINUS_LONG_MAX_LEN) internalFlush();
        int d;
        if (x < 0) {
            if (x == Long.MIN_VALUE) {
                buf[ptr++] = '-'; buf[ptr++] = '9'; buf[ptr++] = '2'; buf[ptr++] = '2';
                buf[ptr++] = '3'; buf[ptr++] = '3'; buf[ptr++] = '7'; buf[ptr++] = '2';
                buf[ptr++] = '0'; buf[ptr++] = '3'; buf[ptr++] = '6'; buf[ptr++] = '8';
                buf[ptr++] = '5'; buf[ptr++] = '4'; buf[ptr++] = '7'; buf[ptr++] = '7';
                buf[ptr++] = '5'; buf[ptr++] = '8'; buf[ptr++] = '0'; buf[ptr++] = '8';
                return this;
            }
            d = len(x = -x);
            buf[ptr++] = '-';
        } else {
            d = len(x);
        }
        int j = ptr += d; 
        while (x > 0) {
            buf[--j] = (byte) ('0' + (x % 10));
            x /= 10;
        }
        return this;
    }

    public FastPrintStream print(double d, int precision) {
        if (d < 0) {
            print('-');
            d = -d;
        }
        d += Math.pow(10, -precision) / 2;
        print((long) d).print('.');
        d -= (long) d;
        for(int i = 0; i < precision; i++){
            d *= 10;
            print((int) d);
            d -= (int) d;
        }
        return this;
    }

    public FastPrintStream print(double d) {
        return print(d, precision);
    }

    public void setPrecision(int precision) {
        this.precision = precision;
    }

    private void internalFlush() {
        try {
            out.write(buf, 0, ptr);
            ptr = 0;
        } catch (java.io.IOException e) {
            throw new java.io.UncheckedIOException(e);
        }
    }

    public void flush() {
        try {
            out.write(buf, 0, ptr);
            out.flush();
            ptr = 0;
        } catch (java.io.IOException e) {
            throw new java.io.UncheckedIOException(e);
        }
    }

    public void close() {
        try {
            out.close();
        } catch (java.io.IOException e) {
            throw new java.io.UncheckedIOException(e);
        }
    }

    private static int len(int x) {
        return
            x >= 1000000000 ? 10 :
            x >= 100000000  ?  9 :
            x >= 10000000   ?  8 :
            x >= 1000000    ?  7 :
            x >= 100000     ?  6 :
            x >= 10000      ?  5 :
            x >= 1000       ?  4 :
            x >= 100        ?  3 :
            x >= 10         ?  2 : 1;
    }

    private static int len(long x) {
        return
            x >= 1000000000000000000l ? 19 :
            x >= 100000000000000000l  ? 18 :
            x >= 10000000000000000l   ? 17 :
            x >= 1000000000000000l    ? 16 :
            x >= 100000000000000l     ? 15 :
            x >= 10000000000000l      ? 14 :
            x >= 1000000000000l       ? 13 :
            x >= 100000000000l        ? 12 :
            x >= 10000000000l         ? 11 : 10;
    }
}


class LinearSieve {
    private final int N;
    private final int primeNum;
    private final int[] minPrimeFactor;
    private final int[] primes;
    public LinearSieve(int n) {
        this.N = n;
        this.minPrimeFactor = new int[N + 1];
        int[] primes = new int[N + 1];
        int primeNum = 0;
        for (int div = 2; div <= N; div++) {
            if (minPrimeFactor[div] == 0) {
                minPrimeFactor[div] = div;
                primes[primeNum++] = div;
            }
            int maxPrime = Math.min(N / div, minPrimeFactor[div]);
            for (int i = 0; i < primeNum; i++) {
                int prime = primes[i];
                if (prime > maxPrime) break;
                minPrimeFactor[prime * div] = prime;
            }
        }
        this.primes = java.util.Arrays.copyOf(primes, primeNum);
        this.primeNum = primeNum;
    }
    public int[] minPrimeFactor() {
        return minPrimeFactor;
    }
    public int[] primes() {
        return primes;
    }
    public int primeNum() {
        return primeNum;
    }
    public OptionalInt minPrimeFactor(int n) {
        int prime = minPrimeFactor[n];
        return prime == 0 ? OptionalInt.empty() : OptionalInt.of(prime);
    }
    public ArrayList<IntPrimePower> factorize(int n) {
        ArrayList<IntPrimePower> primeFactorPowers = new ArrayList<>();
        for (int prime = minPrimeFactor[n]; prime != 0; prime = minPrimeFactor[n]) {
            int index = 0;
            while (n % prime == 0) {
                n /= prime;
                index++;
            }
            primeFactorPowers.add(new IntPrimePower(prime, index));
        }
        return primeFactorPowers;
    }
}