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
#include <bits/stdc++.h>
using namespace std;
unsigned long long my_pow(unsigned long long a, unsigned long long e) {
  return !e ? 1 : (e % 2 ? a * my_pow(a, e - 1) : my_pow(a * a, e / 2));
}
int main() {
  unsigned long long w, m, k;
  cin >> w >> m >> k;
  unsigned long long ans = 0;
  unsigned long long sv = m;
  unsigned long long keta = (m == 0 ? 1 : log10(m) + 1);
  while (true) {
    unsigned long long number = my_pow(10LL, keta) - sv;
    if (keta * number * k <= w) {
      w -= keta * number * k;
      ans += number;
    } else {
      ans += w / (keta * k);
      break;
    }
    sv = my_pow(10LL, keta);
    keta++;
  }
  cout << ans << endl;
  return 0;
}
