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;
inline void Boost() {
  ios::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
}
long long w, m, k, ans, t;
long long cnt(long long x) {
  long long ans = 0;
  while (x) {
    ans++;
    x /= 10;
  }
  return ans;
}
long long power(long long p) {
  long long ans = 1;
  for (int i = 1; i <= p; i++) ans *= 10;
  return ans;
}
int main() {
  Boost();
  int i, j;
  cin >> w >> m >> k;
  w /= k;
  ans = 0;
  long long tmp = cnt(m);
  while ((power(tmp) - m) * tmp <= w) {
    ans += power(tmp) - m;
    w -= (power(tmp) - m) * tmp;
    m = power(tmp);
    tmp++;
  }
  ans += (w / tmp);
  cout << ans;
  return 0;
}
