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;
inline int dig_count(long long n) {
  int count = 0;
  while (n) {
    n = n / 10;
    count++;
  }
  return count;
}
inline long long next_dig_num(int n) {
  long long res = 1;
  for (int i = 0; i < n - 1; i++) {
    res = res * 10;
  }
  return res;
}
int main() {
  long long sum = 0, next, final, left_num, afford_num, m, k, w, i, j;
  int dig;
  cin >> w >> m >> k;
  dig = dig_count(m);
  next = next_dig_num(dig + 1);
  do {
    left_num = next - m;
    afford_num = w / (dig * k);
    final = min(afford_num, left_num);
    sum += final;
    m = next;
    next = next * 10;
    w = w - (final * k * dig);
    dig++;
  } while (final != 0 && w > 0);
  cout << sum << endl;
}
