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>
long long int w, m, k;
using namespace std;
int numD(long long n) {
  int num = 0;
  while (n > 0) {
    n = n / 10;
    num++;
  }
  return num;
}
int main() {
  cin >> w >> m >> k;
  long long int cost = 0;
  if (k > w)
    cout << '0' << endl;
  else {
    int dig = numD(m);
    long long count = 0;
    long long int prev = m;
    while (1) {
      long long int next = 1;
      int d = dig;
      while (d--) {
        next *= 10;
      }
      if ((next - prev) < w / (k * dig)) {
        cost += (next - prev) * k * dig;
        dig = dig + 1;
        count += (next - prev);
        prev = next;
      } else {
        if (cost == w) {
          cout << count << endl;
          break;
        } else {
          count += (w - cost) / (dig * k);
          cout << count << endl;
          break;
        }
      }
    }
  }
  return 0;
}
