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;
unsigned long long pow(unsigned long long a, unsigned long long b) {
  unsigned long long r = 1;
  for (int i = 0; i < b; i++) r = r * a;
  return r;
}
int main() {
  unsigned long long w, m, k;
  cin >> w >> m >> k;
  unsigned long long r = m;
  unsigned long long count = 0;
  while (r != 0) {
    r = r / 10;
    count++;
  }
  unsigned long long z = 0;
  while (w != 0) {
    unsigned long long a = k;
    unsigned long long c = pow(10, count);
    a = a * count;
    z += (w / a) < (c - m) ? (w / a) : (c - m);
    count++;
    w -= ((w / a) < (c - m) ? (w / a) : (c - m)) * a;
    m = pow(10, count - 1);
    if (w / a == 0) break;
  }
  cout << z;
}
