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;
int main() {
  long long w, m, k;
  cin >> w >> m >> k;
  long long temp = m, s = 0;
  long long arr[20], value = 9, maxn = 10, cryst = -1;
  for (int i = 0; i < 18; i++) {
    arr[i] = value;
    if (cryst == -1 && maxn > m) {
      cryst = maxn - m;
    }
    value *= 10;
    maxn *= 10;
    if (temp > 0) s++, temp /= 10;
  }
  long long low = 1, high = cryst, ans = 0, limit = 1e18;
  while (limit / cryst > k * s && w > cryst * k * s) {
    ans += cryst;
    w -= cryst * k * s;
    cryst = arr[s];
    s++;
  }
  ans += w / (k * s);
  cout << ans;
  return 0;
}
