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.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.Scanner;


public class Main {
    static long[] fact;
    public static void main(String[] args) {
//      ArrayList<String> all = new ArrayList<String>();
//      char[] a = "1234567".toCharArray();
//      
//      go(0, a, new char[7], all, new boolean[7]);
//      
//      Collections.sort(all);
//      
//      for(String s : all)
//          System.out.println(s);
        ArrayList<Long> all = new ArrayList<Long>();
        go("0", all);
        Collections.sort(all);
        
        fact = new long[16];
        fact[0] = 1;
        for(int i = 1; i < 16; i++)
            fact[i] = i * fact[i-1];
        
        Scanner r = new Scanner(System.in);
        int n = r.nextInt();
        int k = r.nextInt();
        
        if(n < 15 && k > fact[n]){
            System.out.println(-1);
            return;
        }
        k--;
        
        int start = Math.max(0, n-15);
        int sum = 0;
        
        int length = n - start;
        ArrayList<Integer> a = new ArrayList<Integer>();
        for(int i = 0; i < length; i++)
            a.add(i + start + 1);
            
        boolean[] v = new boolean[length];
        int[] p = new int[length];
        generate(0, length, a, p, v, k);
//      System.out.println(Arrays.toString(p));
        
        for(int i = 0; i < length; i++){
            long index = i + start + 1;
            long val = p[i];
            
            if(all.contains(index) && all.contains(val))sum++;
        }
        
        for(long i: all){
            long index = i-1;
            if(index >= start)break;
            
            sum++;
        }
        
        System.out.println(sum);

    }

    private static int[] generate(int i, int length, ArrayList<Integer> a, int[] p, boolean[] v, long k) {
        if(length == 0){
            return p;
        }else{
            int index = (int) (k / fact[length - 1]);
            
            p[i] = a.get(index);
            a.remove(index);
            
            return generate(i+1, length-1, a, p, v, k % fact[length-1]);
        }
    }

    private static void go(int i, char[] a, char[] p, ArrayList<String> all, boolean[] v) {
        if(i == 7){
            all.add(new String(p));
        }else{
            for(int j = 0; j < 7; j++)if(!v[j]){
                v[j] = true;
                p[i] = a[j];
                go(i+1, a, p, all, v);
                v[j] = false;
            }
        }
    }
    private static void go(String s, ArrayList<Long> all) {
        if(s.length() <= 10){
            if(!s.equals("0"))
                all.add(Long.parseLong(s));
            if(s.length() == 10)return;
        }
        
        go(s+"4", all);
        go(s+"7", all);
    }
}
