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 arr[2000];
void set_arr() {
  int l = 1;
  arr[0] = 9;
  while (arr[l - 1] < 1e17) {
    arr[l] = arr[l - 1] * 10 + 9;
    l++;
  }
}
int main() {
  set_arr();
  int n, tem1, tem2;
  string s, c;
  long long w, m, k, ans = 0, sum = 0;
  cin >> w >> m >> k;
  stringstream ss;
  ss << m;
  string str = ss.str();
  tem1 = str.length();
  int i = 1;
  while (1) {
    long long req = w / k / (tem1);
    if ((req <= arr[tem1 - 1]) && (m - 1 + req <= arr[tem1 - 1])) {
      cout << req + ans;
      break;
    } else {
      ans += arr[tem1 - 1] - m + 1;
      w -= k * (arr[tem1 - 1] - m + 1) * (tem1);
      m = arr[tem1 - 1] + 1;
    }
    tem1++;
  }
  return 0;
}
