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 res;
long long cal(long dg) {
  res = 0;
  for (long i = 1; i <= dg; i++) res = res * 10 + 9;
  return res;
}
long long cal1(long dg) {
  res = 1;
  for (long i = 1; i < dg; i++) res = res * 10 + 0;
  return res;
}
int main() {
  long long w, m, k;
  while (cin >> w >> m >> k) {
    long long low, high, p, a, ans = 0, dig = 0, i;
    low = m;
    while (m != 0) {
      dig++;
      m = m / 10;
    }
    for (i = dig;; i++) {
      high = cal(i);
      p = high - low + 1;
      a = w / (i * k);
      if (a == 0) break;
      ans = ans + min(p, a);
      w -= min(p, a) * i * k;
      low = cal1(i + 1);
    }
    cout << ans << endl;
  }
  return 0;
}
