#include <bits/stdc++.h>
using namespace std;
long long n, m, w, k, ans, t, r, tmp;
int main() {
  cin >> w >> m >> k;
  t = m;
  int tp = 0;
  while (t > 0) {
    t /= 10;
    tp++;
  }
  r = 1;
  for (int i = 1; i <= tp; i++) r *= 10;
  while (w > 0) {
    tmp = w / k / tp;
    if (tmp > (r - m)) {
      w -= (r - m) * k * tp;
      ans += r - m;
      tp++;
      m = r;
      r *= 10;
    } else {
      ans += w / tp / k;
      break;
    }
  }
  cout << ans;
}

### Prompt

Construct a Cpp code solution to the problem outlined:

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;
long long n, m, w, k, ans, t, r, tmp;
int main() {
  cin >> w >> m >> k;
  t = m;
  int tp = 0;
  while (t > 0) {
    t /= 10;
    tp++;
  }
  r = 1;
  for (int i = 1; i <= tp; i++) r *= 10;
  while (w > 0) {
    tmp = w / k / tp;
    if (tmp > (r - m)) {
      w -= (r - m) * k * tp;
      ans += r - m;
      tp++;
      m = r;
      r *= 10;
    } else {
      ans += w / tp / k;
      break;
    }
  }
  cout << ans;
}

```