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 f(long long m) {
  int ans = 0;
  while (m > 0L) {
    m /= 10L;
    ans++;
  }
  return ans;
}
long long g(int n) {
  long long ans = 1;
  while (--n > 0) {
    ans *= 10L;
  }
  return ans;
}
int main() {
  long long w, m, k;
  cin >> w >> m >> k;
  long long lim = w / k;
  int dlen = f(m);
  long long ans = 0;
  long long n = g(dlen + 1) - m;
  if (dlen * n <= lim) {
    ans += n;
    lim -= (long long)dlen * n;
    for (dlen++;; dlen++) {
      n = g(dlen + 1) - g(dlen);
      if (dlen * n >= lim) {
        ans += lim / dlen;
        break;
      }
      ans += n;
      lim -= (long long)dlen * n;
    }
  } else {
    ans = lim / dlen;
  }
  cout << ans << endl;
  return 0;
}
