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.*;
import java.lang.reflect.Array;
import java.util.*;

public class Main {
    static BufferedReader newInput() throws IOException {
        return new BufferedReader(new InputStreamReader(System.in));
    }
    static PrintWriter newOutput() throws IOException {
        return new PrintWriter(System.out);
    }
    public static void main(String[] args) throws IOException {
        BufferedReader in = newInput();
        PrintWriter out = newOutput();
        function(in, out);
        out.flush();
    }
    public static void function(BufferedReader in, PrintWriter out) throws IOException {
        //StringTokenizer t = new StringTokenizer(in.readLine());
        String[] nk = in.readLine().split(" ");
        long n = Integer.parseInt(nk[0]);
        long k = Long.parseLong(nk[1]);

        ArrayList<Integer> nums = new ArrayList<>();
        for (int i = Math.max(1, (int)n-13); i <= (int)n; i++) {
            nums.add(i);
        }

        long fact = factorial(Math.min(n, 14));
        long x = Math.min(n, 14);
        int lucks = lucks(Math.max(1, (int)n-13));

        for (int i = Math.max(1, (int)n-13); i <= n; i++) {
            fact /= x;
            x--;
            int b = (int)((k-1)/fact);
            if (b >= n){
                out.println("-1");
                return;
            }
            k -= (b*fact);
            int num = nums.get(b);
            nums.remove(b);
            if (isLucky(num) && isLucky(i)){
                lucks++;
            }
        }
        out.println(lucks);
    }
    public static long factorial(long num){
        long x = num;
        num--;
        for (;num != 0; num--) {
            x *= num;
        }
        return x;
    }
    public static boolean isLucky(int x){
        for (; x != 0; x /= 10) {
            int b = x % 10;
            if (b != 7 && b != 4){
                return false;
            }
        }
        return true;
    }
    public static int lucks(int max){
        int lucks = 0;
        ArrayList<Integer> luckys = new ArrayList<>();
        luckys.add(4);
        luckys.add(7);
        for (int i = 0; i < 8; i++) {
            luckys = add(luckys);
        }
        for (int i : luckys) {
            if (i < max){
                lucks++;
            }
        }
        return lucks;
    }
    public static int prev = 0;
    public static ArrayList<Integer> add(ArrayList<Integer> lucks){
        int len = lucks.size();
        for (int i = prev; i < len; i++) {
            lucks.add(lucks.get(i)+(int)(4*Math.pow(10, String.valueOf(lucks.get(i)).length())));
        }
        for (int i = prev; i < len; i++) {
            lucks.add(lucks.get(i)+(int)(7*Math.pow(10, String.valueOf(lucks.get(i)).length())));
        }
        prev = len;
        return lucks;
    }
}