#include <bits/stdc++.h>
using namespace std;
int main() {
  string s;
  cin >> s;
  int dp[105][4][2];
  int n = s.size();
  int K;
  cin >> K;
  dp[0][0][0] = 1;
  for (int i = 0; i < n; i++)
    for (int j = 0; j < 4; j++)
      for (int k = 0; k < 2; k++) {
        int nd = s[i] - '0';
        for (int d = 0; d < 10; d++) {
          int ni = i + 1, nj = j, nk = k;
          if (d != 0) nj++;
          if (nj > K) continue;
          if (k == 0) {
            if (d > nd) continue;
            if (d < nd) nk = 1;
          }
          dp[ni][nj][nk] += dp[i][j][k];
        }
      }
  int ans = dp[n][K][0] + dp[n][K][1];
  cout << ans << endl;
}
