/*****/

#include <iostream>
#include <array>
#include <vector>
#include <algorithm>
#include <string>
#include <cmath>
#include <queue>
#include <stack>
#include <map>
#include <iomanip>	//cout << fixed << setprecision(桁数);
#include <stdexcept>

//#define int long long

using namespace std;
using ll = long long;
using ld = long double;
using vecll = vector<long long>;
using pll = pair<long long, long long>;
template<class T> using pr = pair<T, T>;
template<class T> using vec = vector<T>;

#define debug(x) (std::cerr << (x) << "\n")
#define debug_tab(n, x) (std::cerr << strMulti("\t",n) << (x) << "\n")
#define debug_cout(x) (std::cerr << #x << " : " <<  (x) << "\n")
#define debug_tabcout(n, x) (std::cerr << strMulti("\t",n) << #x << " : " <<  (x) << "\n")
#define debug_headcout(h, x) (std::cerr << h << " : " <<  (x) << "\n")
#define debug_tabheadcout(n, h, x) (std::cerr << strMulti("\t",n) << h << " : " <<  (x) << "\n")

#define str(n)	n.toString()

#define rep(i, n) for(ll i=0, i##_len=(n); i<i##_len; ++i)
#define rep1(i, n) for(ll i=1, i##_len=(n); i<=i##_len; ++i)
#define rrep(i, n) for(ll i=(n)-1; i >= 0; --i)
#define rrep1(i, n) for(ll i=(n); i > 0; --i)
#define all(x) (x).begin(), (x).end()
#define pair(a, b) make_pair(a, b)
constexpr int INF = 2000000100;
constexpr ll MOD = 1000000007;	// 10e9+7
template<class T> bool chmax(T& a, T b) { if (a < b) { a = b; return true; } return false; }
template<class T> bool chmin(T& a, T b) { if (a > b) { a = b; return true; } return false; }
template<class T> T divup(T a, T b) { if (a % b == 0) { return a / b; } return a / b + 1; }
std::string strMulti(std::string t, int n) { std::string out = ""; for (int i = 0; i < n; i++) { out += t; } return out; }
template<class T> T math_P(T m, T n) { T ret = 1; for (T i = m; i > m - n; i--) { ret *= i; } return ret; }
template<class T> T math_C(T m, T n) { T ret = math_P(m, n); for (T i = 2; i <= n; i++) { ret /= i; } return ret; }
template<class T> bool compare_by_b(pair<T, T> a, pair<T, T> b) { if (a.second != b.second) { return a.second < b.second; } return a.first < b.first; }
template<class T> T mod_pow(T x, T n, const T& p) { T ret = 1; while (n > 0) { if (n & 1) { (ret *= x) %= p; } (x *= x) %= p; n >>= 1; } return ret; }

/*****/

ll solve(string& N, ll K)
{
	ll L = N.length();

	vec<vec<vecll>> dp(105, vec<vecll>(2, vecll(K + 5, 0)));
	dp[0][0][0] = 1;
	// dp[桁目][未満フラグ][0でない数]

	rep(i, L)
	{
		//debug_cout(i);
		ll D = N[i] - '0';

		rep(j, 2)
		{
			//debug_tabcout(1, j);
			rep(k, K + 1)
			{
				//debug_tabcout(2, k);
				for (int d = 0; d <= (j ? 9 : D); ++d)
				{
					//debug_tabcout(3, d);

					if (d == 0)
						dp[i + 1][j || (d < D)][k] += dp[i][j][k];
					else
						dp[i + 1][j || (d < D)][k + 1] += dp[i][j][k];
				}
			}
		}
	}

	/*rep(i, L + 1)
	{
		debug_cout(i);

		if (i < L)
		{
			ll D = S[i] - '0';
			debug_tabcout(1, D);
		}

		rep(j, 2)
		{
			rep(k, K + 1)
			{
				debug_tabheadcout(1,
					"dp[" << i << "][" << j << "][" << k << "]",
					dp[i][j][k]);
			}
		}
	}*/


	return dp[L][0][K] + dp[L][1][K];
}

void Main()
{
	string N;
	ll K;
	cin >> N >> K;

	cout << solve(N, K);
}

/*****/

int main()
{
	//std::ios::sync_with_stdio(false);
	//std::cin.tie(0);

	//std::cout << std::fixed << std::setprecision(10);

	/*
	while (true)
	{
		Main();
		cout << endl;
	}
	//*/

	Main();

	return 0;
}


Measured memory_bytes: 256