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;
const int INF = 1e9;
const int dx[] = {0, 1, 0, -1};
const int dy[] = {1, 0, -1, 0};
int S(long long k) {
  int cnt = 0;
  while (k) {
    k /= 10;
    ++cnt;
  }
  return cnt;
}
long long w, m, k;
int main() {
  scanf("%I64d%I64d%I64d", &w, &m, &k);
  long long ans = 0, tmp = 1;
  long long q = S(m), p = q;
  long long maxd = w / k;
  while (p--) tmp *= 10;
  while (true) {
    if ((tmp - m) * q + ans <= maxd) {
      ans += tmp - m;
      maxd -= (tmp - m) * q;
      m = tmp;
      tmp *= 10;
      ++q;
    } else {
      ans += maxd / q;
      break;
    }
  }
  printf("%I64d\n", ans);
  return 0;
}
