#include <bits/stdc++.h>
using namespace std;
int main() {
  long long w, m, k, ans = 0;
  cin >> w >> m >> k;
  long long m1 = m, m2 = 1;
  long long s = 0;
  while (m1 > 0) {
    s++;
    m1 /= 10;
    m2 *= 10;
  }
  while (1 == 1) {
    long long kol = m2 - m;
    if (kol <= w / (s * k)) {
      w -= kol * s * k;
      ans += kol;
      m = m2;
      m2 *= 10;
      s++;
    } else {
      ans += w / (s * k);
      break;
    }
  }
  cout << ans;
  return 0;
}

### Prompt

Your challenge is to write 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, k, ans = 0;
  cin >> w >> m >> k;
  long long m1 = m, m2 = 1;
  long long s = 0;
  while (m1 > 0) {
    s++;
    m1 /= 10;
    m2 *= 10;
  }
  while (1 == 1) {
    long long kol = m2 - m;
    if (kol <= w / (s * k)) {
      w -= kol * s * k;
      ans += kol;
      m = m2;
      m2 *= 10;
      s++;
    } else {
      ans += w / (s * k);
      break;
    }
  }
  cout << ans;
  return 0;
}

```