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
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import java.util.StringTokenizer;

public class Sequence2 {
	private static long maxNum(int len) {
		String val = "";
		for (int i = 0; i < len; ++i) {
			val += "9";
		}
		return Long.parseLong(val);
	}

	public static void main(String[] args) throws Exception {
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		PrintWriter pw = new PrintWriter(new OutputStreamWriter(System.out));

		StringTokenizer st = new StringTokenizer(br.readLine());

		long w = Long.parseLong(st.nextToken()), m = Long.parseLong(st
				.nextToken()), k = Long.parseLong(st.nextToken());
		long count = 0;
		int mLen = String.valueOf(m).length();
		long val = maxNum(mLen);
		while (w > 0) {
			long remaining = val - m + 1;
			long costOfOne = mLen * k;
			long totalCost = remaining * costOfOne;
			if ((w/costOfOne) < remaining) {
				remaining = (w) / (costOfOne);
				count += remaining;
				break;
			} else {
				count += remaining;
				w -= totalCost;
			}
			mLen++;
			m = val + 1;
			val *= 10;
			val += 9;
		}
		pw.println(count);
		pw.flush();
		pw.close();
	}
}