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 w, m, k, ans;
bool ok;
long long int cdig(long long int w) {
  long long int n = 0;
  while (w) n++, w /= 10;
  return n;
}
long long int p10(long long int n) {
  long long int ans = 1;
  for (int i = 0; i < n; i++) ans *= 10;
  return ans;
}
int main() {
  ios_base::sync_with_stdio(false);
  cin >> w >> m >> k;
  long long int cur = m;
  while (w > 0) {
    long long int next = p10(cdig(cur));
    long long int amt = w - (next - cur) * k * cdig(cur);
    if (next - cur > 10000000000000000 / k * cdig(cur)) amt = -1;
    if (amt < 0) {
      ans += w / (k * cdig(cur));
      w = 0;
    } else {
      ans += next - cur;
      w -= (next - cur) * k * cdig(cur);
      cur = next;
    }
  }
  cout << ans << '\n';
  return 0;
}
