#include <bits/stdc++.h>
using ll = long long;
using namespace std;
ll mod = 1000000007;
ll n_pow(ll a, ll n) {
  if (n == 0) return 1;
  ll t = n_pow(a, n / 2);
  t *= t;
  t %= mod;
  if (n % 2 == 1) t *= a;
  return t % mod;
}
const int INF = 1001001001;
ll k_1(string s) {
  ll ans = (s.size() - 1) * 9;
  int p = s[0] - '0';
  ans += p;
  return ans;
}
ll k_2(string s) {
  ll n = s.size();
  ll ans = 81 * (n - 1) * (n - 2) / 2;
  int p = s[0] - '0';
  ans += (p - 1) * (n - 1) * 9;
  ans += k_1(s.substr(1));
  return ans;
}
ll k_3(string s) {
  ll n = s.size();
  ll ans = 729 * (n - 1) * (n - 2) * (n - 3) / 6;
  ll p = s[0] - '0';
  ans += (p - 1) * 81 * (n - 1) * (n - 2) / 2;
  ans += k_2(s.substr(1));
  return ans;
}
int main() {
  string s;
  cin >> s;
  ll n = s.size();
  int k;
  cin >> k;
  ll ans;
  if (k == 1) {
    ans = k_1(s);
  } else if (k == 2) {
    ans = k_2(s);
  } else {
    ans = k_3(s);
  }
  cout << ans << endl;
  return 0;
}
