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;
int S(long long n) {
  int a = 0;
  while (n) {
    n /= 10;
    a++;
  }
  return a;
}
long long make(int n) {
  long long a = 1;
  while (n--) {
    a *= 10;
  }
  return a;
}
int main() {
  long long w, m, k;
  cin >> w >> m >> k;
  w /= k;
  long long ans = 0;
  long long temp = 0;
  long long sum = 0;
  int l = S(m);
  temp += (make(l) - m) * l;
  if (temp > w) {
    ans = w / l;
    cout << ans;
    return 0;
  } else {
    ans += (make(l) - m);
  }
  sum = temp;
  while (temp < w) {
    temp += (make(l + 1) - make(l)) * (l + 1);
    if (temp < w) {
      sum = temp;
      ans += (make(l + 1) - make(l));
      l++;
    } else {
      temp -= (make(l + 1) - make(l)) * (l + 1);
      ans += (w - (temp)) / (l + 1);
      cout << ans;
      return 0;
    }
  }
  cout << ans;
  return 0;
}
