Petya loves lucky numbers. Everybody knows that lucky numbers are positive integers whose decimal representation contains only the lucky digits 4 and 7. For example, numbers 47, 744, 4 are lucky and 5, 17, 467 are not.

One day Petya dreamt of a lexicographically k-th permutation of integers from 1 to n. Determine how many lucky numbers in the permutation are located on the positions whose indexes are also lucky numbers.

Input

The first line contains two integers n and k (1 ≤ n, k ≤ 109) — the number of elements in the permutation and the lexicographical number of the permutation.

Output

If the k-th permutation of numbers from 1 to n does not exist, print the single number "-1" (without the quotes). Otherwise, print the answer to the problem: the number of such indexes i, that i and ai are both lucky numbers.

Examples

Input

7 4


Output

1


Input

4 7


Output

1

Note

A permutation is an ordered set of n elements, where each integer from 1 to n occurs exactly once. The element of permutation in position with index i is denoted as ai (1 ≤ i ≤ n). Permutation a is lexicographically smaller that permutation b if there is such a i (1 ≤ i ≤ n), that ai < bi, and for any j (1 ≤ j < i) aj = bj. Let's make a list of all possible permutations of n elements and sort it in the order of lexicographical increasing. Then the lexicographically k-th permutation is the k-th element of this list of permutations.

In the first sample the permutation looks like that:

1 2 3 4 6 7 5

The only suitable position is 4.

In the second sample the permutation looks like that:

2 1 3 4

The only suitable position is 4.

import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.nio.charset.Charset;
import java.util.Arrays;
import java.util.Comparator;

public class CF121C {
    public static void main(String[] args) throws Exception {
        boolean local = System.getProperty("ONLINE_JUDGE") == null;
        boolean async = false;

        Charset charset = Charset.forName("ascii");

        FastIO io = local ? new FastIO(new FileInputStream("D:\\DATABASE\\TESTCASE\\Code.in"), System.out, charset) : new FastIO(System.in, System.out, charset);
        Task task = new Task(io, new Debug(local));

        if (async) {
            Thread t = new Thread(null, task, "dalt", 1 << 27);
            t.setPriority(Thread.MAX_PRIORITY);
            t.start();
            t.join();
        } else {
            task.run();
        }

        if (local) {
            io.cache.append("\n\n--memory -- \n" + ((Runtime.getRuntime().totalMemory() - Runtime.getRuntime().freeMemory()) >> 20) + "M");
        }

        io.flush();
    }

    public static class Task implements Runnable {
        final FastIO io;
        final Debug debug;
        int inf = (int) 1e8;
        int mod = (int) 1e9 + 7;

        public int mod(int val) {
            val %= mod;
            if (val < 0) {
                val += mod;
            }
            return val;
        }

        public int mod(long val) {
            val %= mod;
            if (val < 0) {
                val += mod;
            }
            return (int) val;
        }

        int bitAt(int x, int i) {
            return (x >> i) & 1;
        }

        int bitAt(long x, int i) {
            return (int) ((x >> i) & 1);
        }

        public Task(FastIO io, Debug debug) {
            this.io = io;
            this.debug = debug;
        }

        @Override
        public void run() {
            solve();
        }

        Permutation p;
        int n;
        int total = 0;

        public void solve() {
            n = io.readInt();
            int k = io.readInt();
            p = Permutation.newPermutation(n, k);
            if (p == null) {
                io.cache.append(-1);
                return;
            }

            for (int i = 1; i <= 9; i++) {
                count(i, 0);
            }

            io.cache.append(total);
        }

        public void count(int step, int val) {
            if (step == 0) {
                if (val > n) {
                    return;
                }
                int e = p.elementAt(val);
                if (isValid(e)) {
                    total++;
                }
                return;
            }
            count(step - 1, val * 10 + 4);
            count(step - 1, val * 10 + 7);
        }

        public boolean isValid(int val) {
            if (val % 10 != 4 && val % 10 != 7) {
                return false;
            }
            val /= 10;
            while (val > 0) {
                if (val % 10 != 4 && val % 10 != 7) {
                    return false;
                }
                val /= 10;
            }
            return true;
        }
    }

    public static class Permutation {
        int n;
        int[] tailPerm;

        public static Permutation newPermutation(int n, int k) {
            long p = 1;
            int t = 0;
            for (int i = 1; i <= n && p < k; i++) {
                p = p * i;
                t = i;
            }
            if (p < k) {
                return null;
            }
            int[] tailPerm = new int[t];
            for (int i = 0; i < t; i++) {
                tailPerm[i] = n - i;
            }
            perm(tailPerm, 0, k, p);
            Permutation permutation = new Permutation();
            permutation.n = n;
            permutation.tailPerm = tailPerm;
            return permutation;
        }

        public int elementAt(int i) {
            if (i > n - tailPerm.length) {
                return tailPerm[i - (n - tailPerm.length) - 1];
            }
            return i;
        }

        public static void perm(int[] tailPerm, int offset, int k, long p) {
            if (offset == tailPerm.length) {
                return;
            }
            Arrays.sort(tailPerm, offset, tailPerm.length);
            int remain = tailPerm.length - offset;
            p /= remain;
            for (int i = offset + 1; p < k; i++) {
                Memory.swap(tailPerm, offset, i);
                k -= p;
            }
            perm(tailPerm, offset + 1, k, p);
        }
    }

    public static class Memory {
        public static <T> void swap(T[] data, int i, int j) {
            T tmp = data[i];
            data[i] = data[j];
            data[j] = tmp;
        }

        public static void swap(char[] data, int i, int j) {
            char tmp = data[i];
            data[i] = data[j];
            data[j] = tmp;
        }

        public static void swap(int[] data, int i, int j) {
            int tmp = data[i];
            data[i] = data[j];
            data[j] = tmp;
        }

        public static void swap(long[] data, int i, int j) {
            long tmp = data[i];
            data[i] = data[j];
            data[j] = tmp;
        }

        public static <T> int min(T[] data, int from, int to, Comparator<T> cmp) {
            int m = from;
            for (int i = from + 1; i < to; i++) {
                if (cmp.compare(data[m], data[i]) > 0) {
                    m = i;
                }
            }
            return m;
        }

        public static <T> void move(T[] data, int from, int to, int step) {
            int len = to - from;
            step = len - (step % len + len) % len;
            Object[] buf = new Object[len];
            for (int i = 0; i < len; i++) {
                buf[i] = data[(i + step) % len + from];
            }
            System.arraycopy(buf, 0, data, from, len);
        }

        public static <T> void reverse(T[] data, int f, int t) {
            int l = f, r = t - 1;
            while (l < r) {
                swap(data, l, r);
                l++;
                r--;
            }
        }

        public static void reverse(int[] data, int f, int t) {
            int l = f, r = t - 1;
            while (l < r) {
                swap(data, l, r);
                l++;
                r--;
            }
        }

        public static void copy(Object[] src, Object[] dst, int srcf, int dstf, int len) {
            if (len < 8) {
                for (int i = 0; i < len; i++) {
                    dst[dstf + i] = src[srcf + i];
                }
            } else {
                System.arraycopy(src, srcf, dst, dstf, len);
            }
        }

        public static void fill(int[][] x, int val) {
            for (int[] v : x) {
                Arrays.fill(v, val);
            }
        }

        public static void fill(int[][][] x, int val) {
            for (int[][] v : x) {
                fill(v, val);
            }
        }
    }


    public static class FastIO {
        public final StringBuilder cache = new StringBuilder();
        private final InputStream is;
        private final OutputStream os;
        private final Charset charset;
        private StringBuilder defaultStringBuf = new StringBuilder(1 << 8);
        private byte[] buf = new byte[1 << 13];
        private int bufLen;
        private int bufOffset;
        private int next;

        public FastIO(InputStream is, OutputStream os, Charset charset) {
            this.is = is;
            this.os = os;
            this.charset = charset;
        }

        public FastIO(InputStream is, OutputStream os) {
            this(is, os, Charset.forName("ascii"));
        }

        private int read() {
            while (bufLen == bufOffset) {
                bufOffset = 0;
                try {
                    bufLen = is.read(buf);
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }
                if (bufLen == -1) {
                    return -1;
                }
            }
            return buf[bufOffset++];
        }

        public void skipBlank() {
            while (next >= 0 && next <= 32) {
                next = read();
            }
        }

        public int readInt() {
            int sign = 1;

            skipBlank();
            if (next == '+' || next == '-') {
                sign = next == '+' ? 1 : -1;
                next = read();
            }

            int val = 0;
            if (sign == 1) {
                while (next >= '0' && next <= '9') {
                    val = val * 10 + next - '0';
                    next = read();
                }
            } else {
                while (next >= '0' && next <= '9') {
                    val = val * 10 - next + '0';
                    next = read();
                }
            }

            return val;
        }

        public long readLong() {
            int sign = 1;

            skipBlank();
            if (next == '+' || next == '-') {
                sign = next == '+' ? 1 : -1;
                next = read();
            }

            long val = 0;
            if (sign == 1) {
                while (next >= '0' && next <= '9') {
                    val = val * 10 + next - '0';
                    next = read();
                }
            } else {
                while (next >= '0' && next <= '9') {
                    val = val * 10 - next + '0';
                    next = read();
                }
            }

            return val;
        }

        public double readDouble() {
            boolean sign = true;
            skipBlank();
            if (next == '+' || next == '-') {
                sign = next == '+';
                next = read();
            }

            long val = 0;
            while (next >= '0' && next <= '9') {
                val = val * 10 + next - '0';
                next = read();
            }
            if (next != '.') {
                return sign ? val : -val;
            }
            next = read();
            long radix = 1;
            long point = 0;
            while (next >= '0' && next <= '9') {
                point = point * 10 + next - '0';
                radix = radix * 10;
                next = read();
            }
            double result = val + (double) point / radix;
            return sign ? result : -result;
        }

        public String readString(StringBuilder builder) {
            skipBlank();

            while (next > 32) {
                builder.append((char) next);
                next = read();
            }

            return builder.toString();
        }

        public String readString() {
            defaultStringBuf.setLength(0);
            return readString(defaultStringBuf);
        }

        public int readLine(char[] data, int offset) {
            int originalOffset = offset;
            while (next != -1 && next != '\n') {
                data[offset++] = (char) next;
                next = read();
            }
            return offset - originalOffset;
        }

        public int readString(char[] data, int offset) {
            skipBlank();

            int originalOffset = offset;
            while (next > 32) {
                data[offset++] = (char) next;
                next = read();
            }

            return offset - originalOffset;
        }

        public int readString(byte[] data, int offset) {
            skipBlank();

            int originalOffset = offset;
            while (next > 32) {
                data[offset++] = (byte) next;
                next = read();
            }

            return offset - originalOffset;
        }

        public char readChar() {
            skipBlank();
            char c = (char) next;
            next = read();
            return c;
        }

        public void flush() {
            try {
                os.write(cache.toString().getBytes(charset));
                os.flush();
                cache.setLength(0);
            } catch (IOException e) {
                throw new RuntimeException(e);
            }
        }

        public boolean hasMore() {
            skipBlank();
            return next != -1;
        }
    }

    public static class Debug {
        private boolean allowDebug;

        public Debug(boolean allowDebug) {
            this.allowDebug = allowDebug;
        }

        public void assertTrue(boolean flag) {
            if (!allowDebug) {
                return;
            }
            if (!flag) {
                fail();
            }
        }

        public void fail() {
            throw new RuntimeException();
        }

        public void assertFalse(boolean flag) {
            if (!allowDebug) {
                return;
            }
            if (flag) {
                fail();
            }
        }

        private void outputName(String name) {
            System.out.print(name + " = ");
        }

        public void debug(String name, int x) {
            if (!allowDebug) {
                return;
            }

            outputName(name);
            System.out.println("" + x);
        }

        public void debug(String name, long x) {
            if (!allowDebug) {
                return;
            }
            outputName(name);
            System.out.println("" + x);
        }

        public void debug(String name, double x) {
            if (!allowDebug) {
                return;
            }
            outputName(name);
            System.out.println("" + x);
        }

        public void debug(String name, int[] x) {
            if (!allowDebug) {
                return;
            }
            outputName(name);
            System.out.println(Arrays.toString(x));
        }

        public void debug(String name, long[] x) {
            if (!allowDebug) {
                return;
            }
            outputName(name);
            System.out.println(Arrays.toString(x));
        }

        public void debug(String name, double[] x) {
            if (!allowDebug) {
                return;
            }
            outputName(name);
            System.out.println(Arrays.toString(x));
        }

        public void debug(String name, Object x) {
            if (!allowDebug) {
                return;
            }
            outputName(name);
            System.out.println("" + x);
        }

        public void debug(String name, Object... x) {
            if (!allowDebug) {
                return;
            }
            outputName(name);
            System.out.println(Arrays.deepToString(x));
        }
    }
}
