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;
unsigned long long dig(unsigned long long n) {
  unsigned long long ret = 0;
  while (n != 0) {
    ret++;
    n /= 10;
  }
  return ret;
}
int main() {
  unsigned long long w, m, k;
  cin >> w >> m >> k;
  unsigned long long ans = 0;
  unsigned long long M = m;
  while (true) {
    unsigned long long d = dig(M);
    unsigned long long nex = 1;
    for (int i = 0; i < d; i++) {
      nex *= 10;
    }
    unsigned long long next = nex - M;
    unsigned long long cost = next * k * d;
    if (w < cost)
      break;
    else {
      w -= cost;
      ans += (nex - M);
    }
    M = nex;
  }
  ans += (w / (dig(M) * k));
  cout << ans << endl;
  return 0;
}
