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;
long long w, m, k, n, a[50], j, i;
int main() {
  cin >> w >> m >> k;
  w /= k;
  a[0] = 1;
  for (i = 1; i <= 20; i++) a[i] = a[i - 1] * 10;
  while (w > 0) {
    for (j = 0; j <= 20; j++)
      if (a[j] > m) break;
    j--;
    if (w <= j) break;
    if ((a[j + 1] - m) * (j + 1) <= w) {
      n += (a[j + 1] - m);
      w -= (a[j + 1] - m) * (j + 1);
      m = a[j + 1];
      continue;
    }
    cout << n + (w / (j + 1)) << endl;
    return 0;
  }
  cout << n << endl;
}
