#include <bits/stdc++.h>
int main() {
  long i, k, m, c, cf = 0, cg = 0;
  char n[105];
  scanf("%s", &n);
  scanf("%ld", &k);
  for (c = 0; n[c] != 0; c++) {
    n[c] -= '0';
    if (c > 0) {
      if (cf == 0) {
        cf = n[c];
      } else {
        cf += 9;
      }
    }
    if (c > 1) {
      if (cg == 0) {
        cg = n[c];
      } else {
        cg += 9;
      }
    }
  }
  if (k == 1) {
    m = (c - 1) * 9;
    m += n[0];
  } else if (k == 2) {
    m = (c - 1) * (c - 2) / 2 * 81;
    m += cf + (n[0] - 1) * (c - 1) * 9;
  } else if (k == 3) {
    m = (c - 1) * (c - 2) * (c - 3) / 2 * 243;
    m += (n[0] - 1) * (c - 1) * (c - 2) / 2 * 81;
    m += (c - 2) * (c - 3) / 2 * 81;
    m += cg + (n[1] - 1) * (c - 2) * 9;
  }
  printf("%ld", m);
  return 0;
}
