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;
public class Main {
    public static void main(String[] args){
        Scanner in = new Scanner(System.in);
        BigInteger tengo, voy, costo, res, llego, necesito, cifras;
        tengo = new BigInteger(in.next());
        voy = new BigInteger(in.next());
        costo = new BigInteger(in.next());
        cifras = BigInteger.ZERO;
        llego = BigInteger.ONE;
        res = BigInteger.ZERO;
        while(llego.compareTo(voy) <= 0){
            llego = llego.multiply(BigInteger.TEN);
            cifras = cifras.add(BigInteger.ONE);
        }
        while(tengo.compareTo(BigInteger.ZERO) > 0){
            while(llego.compareTo(voy) <= 0){
                llego = llego.multiply(BigInteger.TEN);
                cifras = cifras.add(BigInteger.ONE);
            }
            necesito = (llego.subtract(voy)).multiply(costo).multiply(cifras);;
            if(necesito.compareTo(tengo) > 0){
                res = res.add(tengo.divide(costo.multiply(cifras)));
                tengo = BigInteger.ZERO;
            }
            else{
                res = res.add(llego.subtract(voy));
                tengo = tengo.subtract(necesito);
            }
            voy = llego;
        }
        System.out.println(res);
    }
}