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 get(long long n) {
  n--;
  if (n < 10) return n;
  unsigned long long ans = 0, nine = 9, len = 1, dig;
  while ((nine * 10) / 9 <= n) {
    ans += len * nine;
    nine *= 10;
    len++;
  }
  nine /= 9;
  dig = ((n / nine) % 10) - 1;
  ans += dig * nine * len;
  ans += ((n % nine) + 1) * len;
  return ans;
}
int main() {
  ios::sync_with_stdio(false);
  unsigned long long w, s, k;
  cin >> w >> s >> k;
  unsigned long long left = 0, right = 1e17;
  while (left < right) {
    unsigned long long mid = (left + right) / 2;
    if (get(s + mid) - get(s) <= w / k)
      left = mid + 1;
    else
      right = mid;
  }
  left--;
  cout << left;
  return 0;
}
