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;
const int maxcs = 18;
long long w, m, k;
long long a[maxcs];
int main() {
  ios ::sync_with_stdio(false);
  cin >> w >> m >> k;
  a[0] = 1;
  for (int i = 1; i < maxcs; i++) a[i] = a[i - 1] * 10;
  w = w / k;
  long long ans = 0;
  for (int i = 1; i < maxcs; i++) {
    if (a[i] < m) continue;
    long long cost = (a[i] - m) * i;
    if (cost <= w) {
      ans += a[i] - m;
      m = a[i];
      w -= cost;
    } else {
      ans += w / i;
      break;
    }
  }
  cout << ans << endl;
  return 0;
}
