#include <bits/stdc++.h>
using namespace std;
int main() {
  long long w, m;
  cin >> w >> m;
  int k;
  cin >> k;
  w /= k;
  long long n = m - 1, x = 9;
  k = 1;
  while (n) {
    if (n < x) {
      w += n * k;
      break;
    }
    w += x * k;
    n -= x;
    x *= 10, k++;
  }
  n = 0, x = 9, k = 1;
  while (w) {
    if (w / k < x) {
      n += w / k;
      break;
    }
    w -= x * k;
    n += x;
    x *= 10, k++;
  }
  cout << n - (m - 1) << '\n';
  return 0;
}

### Prompt

Your task is to create a Cpp solution to the following problem:

We'll define S(n) for positive integer n as follows: the number of the n's digits in the decimal base. For example, S(893) = 3, S(114514) = 6.

You want to make a consecutive integer sequence starting from number m (m, m + 1, ...). But you need to pay S(n)·k to add the number n to the sequence.

You can spend a cost up to w, and you want to make the sequence as long as possible. Write a program that tells sequence's maximum length.

Input

The first line contains three integers w (1 ≤ w ≤ 1016), m (1 ≤ m ≤ 1016), k (1 ≤ k ≤ 109).

Please, do not write the %lld specifier to read or write 64-bit integers in C++. It is preferred to use the cin, cout streams or the %I64d specifier.

Output

The first line should contain a single integer — the answer to the problem.

Examples

Input

9 1 1


Output

9


Input

77 7 7


Output

7


Input

114 5 14


Output

6


Input

1 1 2


Output

0

### Response

```cpp
#include <bits/stdc++.h>
using namespace std;
int main() {
  long long w, m;
  cin >> w >> m;
  int k;
  cin >> k;
  w /= k;
  long long n = m - 1, x = 9;
  k = 1;
  while (n) {
    if (n < x) {
      w += n * k;
      break;
    }
    w += x * k;
    n -= x;
    x *= 10, k++;
  }
  n = 0, x = 9, k = 1;
  while (w) {
    if (w / k < x) {
      n += w / k;
      break;
    }
    w -= x * k;
    n += x;
    x *= 10, k++;
  }
  cout << n - (m - 1) << '\n';
  return 0;
}

```