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 arr[25];
int getlen(long long x) {
  int cnt = 0;
  while (x > 0) {
    x /= 10LL;
    cnt++;
  }
  return cnt;
}
int main() {
  long long w, m, k;
  cin >> w >> m >> k;
  arr[0] = 1;
  for (int i = 1; i <= 20; i++) {
    arr[i] = arr[i - 1] * 10LL;
  }
  int len = getlen(m);
  long long ans = 0;
  do {
    if ((arr[len] - m) * len <= (w / k)) {
      ans += (arr[len] - m);
      long long temp = w % k;
      w /= k;
      w -= ((arr[len] - m)) * len;
      w *= k;
      w += temp;
      m = arr[len];
      len++;
    } else {
      ans += (w / ((long long)len * k));
      w = 0;
    }
  } while (w > 0);
  cout << ans << endl;
  return 0;
}
