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;
long long w, m, k;
long long dp[20];
long long f1(long long num) {
  int cnt = 0;
  long long n = num;
  while (n != 0) {
    n /= 10;
    cnt++;
  }
  long long ans = 0;
  for (int i = 1; i < cnt; ++i) {
    ans += (dp[i] - dp[i - 1]) * i;
  }
  num = num - dp[cnt - 1] + 1;
  ans += (num)*cnt;
  return ans;
}
int first(long long num) {
  long long c1;
  c1 = f1(m - 1);
  long long c2 = f1(num);
  c1 = c2 - c1;
  if (c1 <= (w / k)) return 1;
  return 0;
}
int main() {
  cin >> w >> m >> k;
  dp[0] = 1;
  for (int i = 1; i <= 18; ++i) dp[i] = dp[i - 1] * 10;
  long long s = m, e = 1e17;
  while (s < e) {
    long long mid = (s + e + 1) / 2;
    if (first(mid))
      s = mid;
    else
      e = mid - 1;
  }
  if (first(s))
    cout << s - m + 1 << endl;
  else
    cout << 0 << endl;
  return 0;
}
