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 w, m, k;
int main() {
  scanf("%I64d%I64d%I64d", &w, &m, &k);
  w /= k;
  if (!w) {
    puts("0");
    return 0;
  }
  long long cnt = 0;
  long long tmp = m;
  while (tmp) {
    cnt++;
    tmp /= 10;
  }
  tmp = 1;
  for (int i = 0; i < cnt; i++) tmp *= 10;
  long long x = m - 1, y = tmp - 1;
  while (w) {
    if (w < cnt) break;
    if (w >= (y - x) * cnt) {
      w -= (y - x) * cnt;
      x = y;
      y = y * 10 + 9;
      cnt++;
    } else {
      x += w / cnt;
      w = 0;
      break;
    }
  }
  cout << x - m + 1 << endl;
}
