#include <bits/stdc++.h>
using namespace std;
using ll = long long int;
using ull = unsigned long long int;
using ld = long double;
using pii = pair<int, int>;
using pll = pair<ll, ll>;
int dx[] = {1, 0, -1, 0, 0};
int dy[] = {0, 1, 0, -1, 0};
const int INT_INF = (int)(2e9);
const ll LL_INF = (ll)(2e18);
const int NIL = -1;
static mt19937 _g(time(nullptr));
std::string pad(int num) {
  char buffer[4];
  std::snprintf(buffer, sizeof(buffer), "%03d", num);
  return buffer;
}
inline ll randint(ll a, ll b) {
  ll w = (_g() << 31LL) ^ _g();
  return a + w % (b - a + 1);
}
inline void fast_io() {
  ios_base::sync_with_stdio(false);
  cin.tie(nullptr);
  cout.tie(nullptr);
};
template <typename T>
inline T sign(T x) {
  return T(x > 0) - T(x < 0);
}
template <typename T, typename S>
inline ostream& operator<<(ostream& os, const pair<T, S> p) {
  cout << "[" << p.first << ";" << p.second << "]";
  return os;
}
template <typename T>
inline ostream& operator<<(ostream& os, const vector<T>& v) {
  for (auto el : v) os << el << " ";
  return os;
}
template <typename T>
inline T fetch() {
  T ret;
  cin >> ret;
  return ret;
}
template <typename T>
inline vector<T> fetch_vec(int sz) {
  vector<T> ret(sz);
  for (auto& elem : ret) cin >> elem;
  return ret;
}
ll N, K;
string S;
void input() {
  fast_io();
  cin >> S >> K;
}
ll fact_db[110];
ll fact(ll x) {
  if (fact_db[x]) return fact_db[x];
  if (x == 0 || x == 1) return fact_db[x] = 1LL;
  return fact_db[x] = x * fact(x - 1);
}
ll combi(ll n, ll k) {
  if (k == 0) return 1;
  if (k == 1) return n;
  if (k == 2) return n * (n - 1) / 2;
  if (k == 3) return n * (n - 1) * (n - 2) / 6;
  return fact(n) / fact(n - k) / fact(k);
}
ll calc(ll N, ll K) {
  if (K == 0) return 1;
  string s = to_string(N);
  int m = s.size() - 1;
  ll res = 0;
  res += combi(m, K) * pow(9, K);
  if (s[0] >= '2') res += combi(m, K - 1) * pow(9, K - 1) * (s[0] - '0' - 1);
  s[0] = '0';
  ll n = stoi(s);
  res += calc(n, K - 1);
  return res;
}
ll calc(string& s, ll K) {
  if (K == 0) return 1;
  int m = s.size() - 1;
  ll res = 0;
  res += combi(m, K) * pow(9, K);
  if (s[0] >= '2') res += combi(m, K - 1) * pow(9, K - 1) * (s[0] - '0' - 1);
  s.erase(0, 1);
  res += calc(s, K - 1);
  return res;
}
int solve() {
  input();
  cout << calc(S, K) << endl;
  return 0;
}
int main() {
  solve();
  return 0;
}
