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;
const int MOD = 1e9 + 7;
const int SIZE = 1e6 + 10;
const long long INF = 1e18;
long long up[18];
int main() {
  up[0] = 1;
  up[1] = 10;
  for (int i = (2); i < (18); ++i) up[i] = up[i - 1] * 10;
  long long w, m, k;
  cin >> w >> m >> k;
  long long ll = 0, rr = w;
  while (ll < rr) {
    long long mm = (ll + rr + 1) >> 1;
    long long need = 0;
    for (int i = (1); i < (18); ++i) {
      long long mi = max(up[i - 1], m);
      long long ma = min(up[i], m + mm);
      if (mi < ma) {
        if (ma - mi > INF / (i * k)) {
          need = INF;
          break;
        }
        need += i * k * (ma - mi);
      }
    }
    if (need > w)
      rr = mm - 1;
    else
      ll = mm;
  }
  cout << ll;
  return 0;
}
