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 len(long long n) {
  int ans = 0;
  while (n) {
    ans++;
    n /= 10;
  }
  return ans;
}
int main() {
  long long ans = 0, w, m, k;
  cin >> w >> m >> k;
  for (int sz = len(m);; sz++) {
    long long p1 = 1;
    for (int i = 0; i < sz; i++) p1 *= 10;
    long long h1 = p1 - m;
    long long div = min(h1, (w / (k * sz)));
    w -= (div * k * sz);
    ans += div;
    if (div < h1) break;
    m = p1;
  }
  cout << ans << endl;
  return 0;
}
