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 power(long long i, long long j) {
  while (j > 1 && j--) {
    i *= 10;
  }
  return i;
}
int main() {
  long long w, m, k;
  cin >> w >> m >> k;
  long long len = 0, sm = m;
  while (sm > 0) {
    len++;
    sm /= 10;
  }
  long long mx = 0;
  for (int i = len; i < 18; ++i) {
    long long number =
        i == len ? power(10ll, i) - m : power(10ll, i) - power(10ll, i - 1);
    long long equation = min(number, w / (i * k));
    if (equation <= 0) break;
    w -= equation * k * i;
    mx += equation;
  }
  cout << mx << endl;
}
