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>
long long gcd(long long a, long long b) { return b == 0 ? a : gcd(b, a % b); }
using namespace std;
long long w, m, k;
long long getw(long long m) {
  if (m == 0) return 1;
  long long sum = 0;
  while (m) {
    m /= 10;
    sum++;
  }
  return sum;
}
int main() {
  while (~scanf("%I64d%I64d%I64d", &w, &m, &k)) {
    long long we = getw(m);
    w /= k;
    long long f = 1LL;
    for (long long i = 0; i < we; i++) f *= 10;
    if (we * (f - m) >= w) {
      cout << w / we << endl;
      continue;
    }
    w -= we * (f - m);
    long long ans = f - m;
    f = 9LL;
    for (long long i = 0; i < we; i++) f *= 10;
    for (long long i = we + 1;; i++) {
      if (f * i >= w) {
        ans += w / i;
        cout << ans << endl;
        break;
      }
      ans += f;
      w -= i * f;
      f *= 10;
    }
  }
  return 0;
}
