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 int w, m, k;
long long int num_dig(long long int n) {
  int digits = 0, i = 0;
  long long int result = 0;
  long long int temp = n, temp2 = 9, temp3 = 1;
  while (temp) {
    digits++;
    temp /= 10;
  }
  for (i = 1; i < digits; i++) {
    result += i * temp2;
    temp2 = temp2 * 10;
    temp3 = temp3 * 10;
  }
  result = result + digits * (n - temp3 + 1);
  return result;
}
bool is_valid(long long int x) {
  if (num_dig(m + x - 1) - num_dig(m - 1) <= w) {
    return true;
  } else
    return false;
}
long long int binary_search(long long int l, long long int r) {
  if (l == r) return l;
  if (l + 1 == r) {
    if (is_valid(r))
      return r;
    else
      return l;
  }
  long long int mid = (l + r) / 2;
  if (is_valid(mid))
    return binary_search(mid, r);
  else
    return binary_search(l, mid);
}
int main() {
  cin >> w >> m >> k;
  w = w / k;
  cout << binary_search(0, w) << endl;
  return 0;
}
