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 w, m, k;
long long comp;
long long getpre(long long a) {
  long long tmp = 1, ct = 0;
  while (a >= tmp) tmp *= 10, ++ct;
  tmp /= 10;
  long long t = 1;
  long long ans = 0;
  for (long long i = 1; i < ct; ++i) ans += i * 9 * t, t *= 10;
  ans += (a - tmp + 1) * ct;
  return ans;
}
bool judge(long long len) {
  long long tl = m - 1;
  long long tr = m + len - 1;
  if (getpre(tr) - getpre(tl) <= comp) return true;
  return false;
}
int main() {
  cin >> w >> m >> k;
  long long l = 0, r = w / k + 1, ans = 0;
  comp = r - 1;
  while (l <= r) {
    long long mid = (l + r) >> 1;
    if (judge(mid))
      l = mid + 1, ans = mid;
    else
      r = mid - 1;
  }
  cout << ans << endl;
}
