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.math.BigInteger;
import java.util.Scanner;

/*
 * To change this template, choose Tools | Templates
 * and open the template in the editor.
 */

/**
 *
 * @author Aleksandr
 */
public class Main {

    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {
        Scanner s = new Scanner(System.in);
        long w = s.nextLong();
        long m = s.nextLong();
        long k = s.nextLong();
        BigInteger result = new BigInteger("0");
        BigInteger bigW = new BigInteger(String.valueOf(w));
        BigInteger bigM = new BigInteger(String.valueOf(m));
        BigInteger bigK = new BigInteger(String.valueOf(k));
        BigInteger bigCostNow = new BigInteger("0");
        while (bigW.compareTo(new BigInteger("0")) > 0) {
            int countRazriad = bigM.toString().length();
            BigInteger upperNum = new BigInteger(getUpperNum(bigM));
            bigCostNow = upperNum.subtract(bigM).multiply(bigK).multiply(new BigInteger(String.valueOf(countRazriad)));
            if (bigCostNow.compareTo(bigW) <= 0) {
                result = result.add(upperNum.subtract(bigM));
                bigW = bigW.subtract(bigCostNow);
            } else {
                result = result.add(bigW.divide(bigK).divide(new BigInteger(String.valueOf(countRazriad))));
                break;
            }
            bigM = upperNum.add(new BigInteger("0"));           
        }
        System.out.println(result);
    }
    
    private static String getUpperNum(BigInteger a) {
        String result = "";
        String m = a.toString();
        for (int i = 0; i < m.length(); i++) {
            result += "0";
        }
        return "1" + result;
    }
}
