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 main() {
  long long w, m, k;
  while (~scanf("%I64d%I64d%I64d", &w, &m, &k)) {
    w /= k;
    long long s = 0;
    int x = 0;
    long long mm = m;
    while (mm) {
      mm /= 10;
      x++;
    }
    long long mmm = 1;
    for (int i = 0; i < x; i++) {
      mmm *= 10;
    }
    while (w > 0) {
      long long mx = x * (mmm - m);
      if (w >= mx) {
        s += (mmm - m);
        w -= mx;
      } else {
        s += (w / x);
        w = 0;
      }
      m = mmm;
      mmm *= 10;
      x++;
    }
    printf("%I64d\n", s);
  }
}
