using System;
using System.Collections.Generic;
using System.Linq;
using static System.Math;

namespace CSharp
{
    static class Program
    {
        static void Main(string[] args)
        {
            string n = ReadString();
            int k = ReadInt();
            long ans = Solve(n, 0, true, k, new long?[n.Length + 1, 10, k + 1]);
            Console.WriteLine(ans);
        }

        static long Solve(string n, int index, bool restrict, int remain, long?[,,] memo)
        {
            if (memo[index, restrict ? 1 : 0, remain].HasValue)
            {
                return memo[index, restrict ? 1 : 0, remain].GetValueOrDefault();
            }

            if (index >= n.Length)
            {
                return remain == 0 ? 1 : 0;
            }

            long ans = 0;

            ans += Solve(n, index + 1, restrict && n[index] - '0' == 0, remain, memo);

            if (remain > 0)
            {
                int maximum = restrict ? n[index] - '0' : 9;
                for (int digit = 1; digit <= maximum; digit++)
                {
                    bool nextRestirct = restrict && n[index] - '0' == digit;
                    ans += Solve(n, index + 1, nextRestirct, remain - 1, memo);
                }
            }

            return (memo[index, restrict ? 1 : 0, remain] = ans).GetValueOrDefault();
        }

        #region Helpers

        static int[] ReadIntArray() => Console.ReadLine().Split().Select(s => int.Parse(s)).ToArray();
        static long[] ReadLongArray() => Console.ReadLine().Split().Select(s => long.Parse(s)).ToArray();

        static int[] ReadLineIntArray(int count) => Enumerable.Repeat(0, count).Select(_ => int.Parse(Console.ReadLine())).ToArray();
        static long[] ReadLineLongArray(int count) => Enumerable.Repeat(0, count).Select(_ => long.Parse(Console.ReadLine())).ToArray();

        static string ReadString() => Console.ReadLine();
        static int ReadInt() => int.Parse(Console.ReadLine());
        static long ReadLong() => long.Parse(Console.ReadLine());

        static void ReadInt(out int first)
        {
            var array = ReadIntArray();
            first = array[0];
        }

        static void ReadInt(out int first, out int second)
        {
            var array = ReadIntArray();
            first = array[0];
            second = array[1];
        }

        static void ReadInt(out int first, out int second, out int third)
        {
            var array = ReadIntArray();
            first = array[0];
            second = array[1];
            third = array[2];
        }

        static void ReadInt(out int first, out int second, out int third, out int fourth)
        {
            var array = ReadIntArray();
            first = array[0];
            second = array[1];
            third = array[2];
            fourth = array[3];
        }

        static void ReadLong(out long first)
        {
            var array = ReadLongArray();
            first = array[0];
        }

        static void ReadLong(out long first, out long second)
        {
            var array = ReadLongArray();
            first = array[0];
            second = array[1];
        }

        static void ReadLong(out long first, out long second, out long third)
        {
            var array = ReadLongArray();
            first = array[0];
            second = array[1];
            third = array[2];
        }

        static void ReadLong(out long first, out long second, out long third, out long fourth)
        {
            var array = ReadLongArray();
            first = array[0];
            second = array[1];
            third = array[2];
            fourth = array[3];
        }

        #endregion
    }
}

Measured memory_bytes: 13268