#include <bits/stdc++.h>
using namespace std;
string s;
int num[105], k, n;
int f(int p, int k) {
  if (k < 0) return 0;
  if (k == 0) return 1;
  if (p <= 0) return 0;
  return f(p - 1, k) + 9 * f(p - 1, k - 1);
}
int solve() {
  int sum = 0;
  int kk = k;
  for (int i = 0; i < n; i++) {
    if (num[i] != 0) {
      sum += f(i, kk) + (num[i] - 1) * f(i, kk - 1);
      kk--;
    }
  }
  if (kk == 0) sum++;
  if (kk == 1) sum += num[0];
  return sum;
}
int main() {
  cin >> s >> k;
  n = s.size();
  for (int i = 0; i < n; i++) num[i] = s[i] - '0';
  cout << solve();
  return 0;
}
