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 a[20];
long long b[20];
int getbit(long long x) {
  int ret = 0;
  while (x) {
    x /= 10;
    ++ret;
  }
  return ret;
}
int main() {
  a[1] = 9;
  b[1] = 9;
  for (int i = 2; i <= 18; ++i) b[i] = b[i - 1] * 10 + 9;
  for (int i = 2; i <= 18; ++i) a[i] = a[i - 1] * 10;
  long long w, m, k;
  while (cin >> w >> m >> k) {
    long long num = getbit(m);
    long long cnt = b[num] - m + 1;
    long long ans = 0;
    if (w <= num * k * cnt || (num * k * cnt) <= 0) {
      ans = w / (num * k);
    } else {
      ans = cnt;
      w -= cnt * num * k;
      for (int i = num + 1; w > 0; ++i) {
        if (w <= a[i] * i * k || a[i] * i * k <= 0) {
          ans += w / (i * k);
          break;
        } else {
          ans += a[i];
          w -= a[i] * k * i;
        }
      }
    }
    cout << ans << endl;
  }
  return 0;
}
