#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using ull = unsigned long long;
using comp = complex<double>;
const ll MOD = 1000000007LL;
const double PI = 3.14159265358979323846;
inline int toint(string s) {
  int v;
  istringstream sin(s);
  sin >> v;
  return v;
}
template <class t>
inline string tostring(t x) {
  ostringstream sout;
  sout << x;
  return sout.str();
}
using Edge = pair<ll, ll>;
ll calc_seq9(ll n, ll k) {
  if (n < k) {
    return 0LL;
  }
  ll res = 1LL;
  for (ll i = 0; i < k; ++i) {
    res *= 9LL;
    res *= n - i;
  }
  for (ll i = 0; i < k; ++i) {
    res /= i + 1LL;
  }
  return res;
}
ll calc(string n, ll k, vector<vector<ll>>& dp) {
  if (dp[n.size()][k] != -1) {
    return dp[n.size()][k];
  }
  if (k == 0) {
    return 1LL;
  }
  if (n.size() == 0) {
    return 0LL;
  }
  ll top_digit = (ll)(n[0] - '0');
  ll res = 0LL;
  res += calc_seq9(n.size() - 1, k);
  res += calc_seq9(n.size() - 1, k - 1) * (top_digit - 1);
  res += calc(n.substr(1), k - 1, dp);
  dp[n.size()][k] = res;
  return res;
}
int main() {
  cin.tie(0);
  ios::sync_with_stdio(false);
  string N;
  ll K;
  cin >> N >> K;
  vector<vector<ll>> dp(N.size() + 1);
  for (ll i = 0; i < dp.size(); ++i) {
    dp[i] = vector<ll>(K + 1, -1LL);
    dp[i][0] = 1LL;
  }
  ll res = 0LL;
  res = calc(N, K, dp);
  cout << res << endl;
  return 0;
}
