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 char IN[] = "_.in";
const char OUT[] = "_.out";
int ntest = 0, test;
unsigned long long w, m, k;
unsigned long long lt[20];
int main() {
  cin >> w >> m >> k;
  stringstream ss;
  string s;
  ss << m;
  ss >> s;
  int tg = s.length();
  lt[0] = 1;
  for (int i = (1); i <= (17); i++) lt[i] = lt[i - 1] * 10;
  long long now = m;
  long long cs = tg;
  long long res = 0;
  long long luu;
  for (int i = (tg); i <= (17); i++) {
    if (w < (lt[i] - now) * k * cs) {
      luu = i;
      break;
    }
    w = w - (lt[i] - now) * k * cs;
    res += lt[i] - now;
    cs++;
    now = lt[i];
  }
  if (w > 0) {
    long long nick = w / luu / k;
    res += nick;
  }
  cout << res;
  return 0;
}
