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 sum(long long x) {
  long long pot = 1;
  int dig = 1;
  long long ans = 0;
  while (pot <= x) pot *= 10, dig++;
  pot /= 10;
  dig--;
  while (pot) {
    ans += (x - pot + 1) * dig;
    x = pot - 1;
    pot /= 10;
    dig--;
  }
  return ans;
}
int main(void) {
  long long w, m, k;
  cin >> w >> m >> k;
  long long c = w / k;
  long long beg = 0, end = 1000000000000000000LL, h;
  long long base = sum(m - 1);
  while (beg <= end) {
    h = (beg + end) / 2;
    if (sum(h) - base > c)
      end = h - 1;
    else
      beg = h + 1;
  }
  if (sum(h) - base > c) h--;
  cout << h - m + 1 << endl;
  return 0;
}
