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;
unsigned long long S(unsigned long long x) {
  unsigned long long res = 0;
  while (x > 0) {
    res++;
    x /= 10;
  }
  return res;
}
int main() {
  unsigned long long w, m, k;
  unsigned long long c[19] = {0};
  c[0] = 1;
  for (int i = 1; i <= 18; i++) c[i] = c[i - 1] * 10LL;
  cin >> w >> m >> k;
  unsigned long long res = 0;
  unsigned long long len = S(m);
  unsigned long long rest = 1;
  rest = c[len];
  rest -= m;
  if (rest * len * k > w) {
    res = w / (len * k);
  } else {
    unsigned long long tmp = rest * len * k;
    res += rest;
    len++;
    for (; tmp + c[len] / 10LL * 9LL * len * k <= w; len++) {
      res += c[len] / 10LL * 9LL;
      tmp += c[len] / 10LL * 9LL * len * k;
    }
    res += (w - tmp) / (len * k);
  }
  cout << res << endl;
}
