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;
string s;
unsigned long long w, m, k;
unsigned long long f(unsigned long long x) {
  unsigned long long ans = 0;
  while (x) {
    ans++;
    x /= 10;
  }
  return ans;
}
int main() {
  cin >> w >> m >> k;
  unsigned long long ds = f(m);
  unsigned long long dn = m;
  unsigned long long d = (unsigned long long)pow(10, (double)ds);
  unsigned long long ans = 0;
  while (w >= ds * k) {
    if (d - dn < w / (ds * k)) {
      unsigned long long diff = w - (d - dn) * ds * k;
      if (diff < 0) {
        w = 0;
        break;
      } else {
        ans += (d - dn);
        w = diff;
      }
    } else {
      unsigned long long diff = w - w / (ds * k) * ds * k;
      if (diff < 0) {
        w = 0;
        break;
      } else {
        ans += w / (ds * k);
        w = diff;
      }
    }
    dn = d;
    ds++;
    d *= 10;
  }
  cout << ans << endl;
  return 0;
}
