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 static java.util.Arrays.*;
import static java.lang.Math.*;
import static java.math.BigInteger.*;
import java.util.*;
import java.math.*;
import java.io.*;

public class C implements Runnable
{
	String file = "input";
	
	boolean TEST = false;
	
	void solve() throws IOException
	{
		int m = nextInt(), k = nextInt();
		list = new ArrayList<Long>();
		gen(0);
		
		int n = min(15, m);
		long[] a = new long[15];
		boolean[] chosen = new boolean[15];
		for(int i = 0; i < n; i++)
		{
			for(int j = 0; j < n; j++)
				if(!chosen[j])
				{
					if(fact(n - i - 1) >= k)
					{
						a[i] = j + 1;
						chosen[j] = true;
						break;				
					}
					else
					{
						k -= fact(n - i - 1);
					}
				}
		}
	    if(k != 1) 
	    {
	    	out.println(-1);
	    	return;
	    }
	    int res = 0;
	    if(m <= 15)
	    {
	    	for(int i = 0; i < m; i++)
	    		if(isLucky(i + 1) && isLucky(a[i])) res++;
	    	out.println(res);
	    }
	    else
	    {
	    	int left = m - 15;
	    	for(long x : list)
	    		if(x <= left) res++;
	    	for(int i = 0; i < n; i++)
	    		if(isLucky(i + left + 1) && isLucky(a[i] + left)) res++;
	    	out.println(res);
	    }
		 
	}
	List<Long> list;
	boolean isLucky(long n)
	{
		while(n > 0)
		{
			long q = n % 10;
			if(q != 4 && q != 7) return false;
			n /= 10;
		}
		return true;
	}
	

	void gen(long x)
	{
		if(x > 10000000000L) return;
		if(x > 0) list.add(x);
		gen(x * 10 + 4);
		gen(x * 10 + 7);
	}
	
	long fact(int n)
	{
	    long res = 1;
	    for(int i = 2; i <= n; i++) res *= i;
	    return res;
	}
	
	String next() throws IOException
	{
		while(st == null || !st.hasMoreTokens()) st = new StringTokenizer(input.readLine());
		return st.nextToken();
	}
	
	int nextInt() throws IOException
	{
		return Integer.parseInt(next());
	}
	
	long nextLong() throws IOException
	{
		return Long.parseLong(next());
	}
	
	double nextDouble() throws IOException
	{
		return Double.parseDouble(next());
	}
	
	void print(Object... o)
	{
		System.out.println(deepToString(o));
	}
	
	void gcj(Object o)
	{
		String s = String.valueOf(o);
		out.println("Case #" + test + ": " + s);
		System.out.println("Case #" + test + ": " + s);
	}
	
	BufferedReader input;
	PrintWriter out;
	StringTokenizer st;
	int test;
	
	void init() throws IOException
	{
		if(TEST) input = new BufferedReader(new FileReader(file + ".in")); 
		else input = new BufferedReader(new InputStreamReader(System.in));
		out = new PrintWriter(new BufferedOutputStream(System.out));
	}
	
	public static void main(String[] args) throws IOException
	{
		new Thread(null, new C(), "", 1 << 20).start();
	}
	
	public void run()
	{
		try
		{
			init();
			if(TEST) 
			{
				int runs = nextInt();
				for(int i = 0; i < runs; i++) solve();
			}
			else solve();
			out.close();		
		}
		catch(Exception e)
		{
			e.printStackTrace();
			System.exit(1);
		}
	}
}