Vasya will fancy any number as long as it is an integer power of two. Petya, on the other hand, is very conservative and only likes a single integer p (which may be positive, negative, or zero). To combine their tastes, they invented p-binary numbers of the form 2^x + p, where x is a non-negative integer.

For example, some -9-binary ("minus nine" binary) numbers are: -8 (minus eight), 7 and 1015 (-8=2^0-9, 7=2^4-9, 1015=2^{10}-9).

The boys now use p-binary numbers to represent everything. They now face a problem: given a positive integer n, what's the smallest number of p-binary numbers (not necessarily distinct) they need to represent n as their sum? It may be possible that representation is impossible altogether. Help them solve this problem.

For example, if p=0 we can represent 7 as 2^0 + 2^1 + 2^2.

And if p=-9 we can represent 7 as one number (2^4-9).

Note that negative p-binary numbers are allowed to be in the sum (see the Notes section for an example).

Input

The only line contains two integers n and p (1 ≤ n ≤ 10^9, -1000 ≤ p ≤ 1000).

Output

If it is impossible to represent n as the sum of any number of p-binary numbers, print a single integer -1. Otherwise, print the smallest possible number of summands.

Examples

Input


24 0


Output


2


Input


24 1


Output


3


Input


24 -1


Output


4


Input


4 -7


Output


2


Input


1 1


Output


-1

Note

0-binary numbers are just regular binary powers, thus in the first sample case we can represent 24 = (2^4 + 0) + (2^3 + 0).

In the second sample case, we can represent 24 = (2^4 + 1) + (2^2 + 1) + (2^0 + 1).

In the third sample case, we can represent 24 = (2^4 - 1) + (2^2 - 1) + (2^2 - 1) + (2^2 - 1). Note that repeated summands are allowed.

In the fourth sample case, we can represent 4 = (2^4 - 7) + (2^1 - 7). Note that the second summand is negative, which is allowed.

In the fifth sample case, no representation is possible.
import javafx.util.Pair;
import java.io.*;
import java.util.*;
import static java.lang.Math.*;

public class Main implements Runnable
{
    boolean multiple = false;
    long MOD = 998244353;

    @SuppressWarnings("Duplicates")
    void solve() throws Exception
    {
        long n = sc.nextLong();
        int p = sc.nextInt();
        int ans = 100;
        for (int nums = 1; nums < 40; nums++)
        {
            long target = n - (nums * p);
            String temp = Long.toBinaryString(target);
            if (target <= 0) continue;
            int count = 0;
            for (char c : temp.toCharArray())
                if (c == '1') count++;
            if (count <= nums && target >= nums)
                ans = min(ans, nums);
        }
        if (ans == 100) System.out.println(-1);
        else System.out.println(ans);
    }

    /*I/O, and other boilerplate*/ @Override public void run() { try { in = new BufferedReader(new InputStreamReader(System.in));out = new PrintWriter(System.out);sc = new FastScanner(in);if (multiple) { int q = sc.nextInt();for (int i = 0; i < q; i++) solve(); } else solve(); } catch (Throwable uncaught) { Main.uncaught = uncaught; } finally { out.close(); }} public static void main(String[] args) throws Throwable{ Thread thread = new Thread(null, new Main(), "", (1 << 26));thread.start();thread.join();if (Main.uncaught != null) {throw Main.uncaught;} } static Throwable uncaught; BufferedReader in; FastScanner sc; PrintWriter out; } class FastScanner { BufferedReader in; StringTokenizer st; public FastScanner(BufferedReader in) {this.in = in;}public String nextToken() throws Exception { while (st == null || !st.hasMoreTokens()) { st = new StringTokenizer(in.readLine()); }return st.nextToken(); }public int nextInt() throws Exception { return Integer.parseInt(nextToken()); }public long nextLong() throws Exception { return Long.parseLong(nextToken()); }public double nextDouble() throws Exception { return Double.parseDouble(nextToken()); }
}