#include <bits/stdc++.h>
using namespace std;
int ctoi(char c) {
  switch (c) {
    case '0':
      return 0;
    case '1':
      return 1;
    case '2':
      return 2;
    case '3':
      return 3;
    case '4':
      return 4;
    case '5':
      return 5;
    case '6':
      return 6;
    case '7':
      return 7;
    case '8':
      return 8;
    case '9':
      return 9;
    default:
      return 0;
  }
}
int64_t combination(size_t s, int k) {
  if (s < k) return 0;
  int64_t bunbo = 1, bunsi = 1;
  for (int i = k; i > 0; i--) {
    bunbo *= i;
    bunsi *= (s - i + 1);
  }
  return bunsi / bunbo;
}
int main() {
  int64_t N, K;
  string str;
  cin >> str;
  cin >> K;
  int64_t total = 0;
  for (int i = K; i > 0; i--) {
    total += combination(str.length() - K + i - 1, i) * pow(9, i);
    total += (ctoi(str[K - i]) - 1) *
             combination(str.length() - K + i - 1, i - 1) * pow(9, i - 1);
    if (i == 1) total++;
  }
  cout << total << endl;
}
