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;
int numdigits(long long m) {
  int ret = 0;
  while (m) {
    m /= 10;
    ret++;
  }
  return ret;
}
long long extract(int x) {
  long long last = 10, first = 10;
  x -= 2;
  while (x--) {
    first *= 10;
  }
  last *= first;
  return (last - first);
}
long long T[23];
int main() {
  long long w, m, ans = 0, k;
  cin >> w >> m >> k;
  int digits = numdigits(m);
  int copy = digits;
  long long base = 10;
  copy--;
  while (copy--) base *= 10;
  T[digits] = base - m;
  for (int i = digits + 1; i <= 23; i++) T[i] = extract(i);
  for (int i = digits; i <= 23 && w > 0; i++) {
    if (w / (i * k) == 0) {
      break;
    }
    long long x = (w / (i * k)) >= T[i] ? T[i] : (w / (i * k));
    ans += x;
    w -= x * i * k;
  }
  cout << ans;
  return 0;
}
