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 get_len(unsigned long long x) {
  int ret = 0;
  while (x) {
    x /= 10;
    ret++;
  }
  return ret;
}
int main(void) {
  unsigned long long w, m, k;
  while (cin >> w >> m >> k) {
    int len = get_len(m);
    unsigned long long mx = 0;
    for (int i = 1; i <= len; ++i) {
      mx = mx * 10 + 9;
    }
    unsigned long long ans = 0;
    unsigned long long cost = (mx - m + 1) * k * len;
    while (cost <= w) {
      w -= cost;
      ans += (mx - m + 1);
      len++;
      m = mx + 1;
      mx = mx * 10 + 9;
      cost = (mx - m + 1) * k * len;
    }
    ans += w / (len * k);
    cout << ans << endl;
  }
  return 0;
}
