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 cnt[21], p[21];
long long w, m, k;
void initcnt() {
  for (int i = 1; i < 21; i++) {
    cnt[i] = i == 1 ? 9 : (cnt[i - 1] * 10ll);
    p[i] = i == 1 ? 10 : (p[i - 1] * 10ll);
  }
}
int s(long long num) {
  int res = 0;
  while (num) {
    num /= 10ll;
    res++;
  }
  return res;
}
long long solv() {
  int bit = s(m);
  long long res = 0;
  long long a = p[bit];
  long long dif = (a - m);
  if (dif * (long long)bit >= w) {
    return w / bit;
  }
  res += dif;
  w -= dif * (long long)bit;
  bit++;
  while (w - cnt[bit] * bit >= 0) {
    w -= cnt[bit] * bit;
    res += cnt[bit];
    bit++;
  }
  res += w / bit;
  return res;
}
int main() {
  initcnt();
  cin >> w >> m >> k;
  w /= k;
  cout << solv() << endl;
  return 0;
}
