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.*;
import  java.util.Scanner;

public class cf373b
{
    private static long w, m, k, d;
    private static int mul;
    
    public static void init()
    {
        d = 10;
        mul = 1;
        while (m + 1 >= d) 
        {
            d *= 10;
            ++mul;
        }
        if (w < (d - m) * mul)
        {
            m += w / mul - 1;
            w = w % mul;
        }
        else 
        {
            w -= (d - m) * mul;
            m += d - m - 1;
        }
        d *= 10;
        ++mul;
    }
    
    public static void main(String[] args) throws IOException
    {
        Scanner in = new Scanner(System.in);
        w = in.nextLong();
        m = in.nextLong();
        k = in.nextLong();
        long mp = m;
        in.close();
        w = w / k;
        init();
        
        //System.out.println(w+" "+m+" "+d+" "+mul);
                        
        while (w >= mul)
        {
            if (w < (d - m - 1) * mul)
            {
                m += w / mul;
                w = w % mul;
            }
            else 
            {
                w -= (d - m - 1) * mul;
                m += d - m - 1;
            }
            d *= 10;
            ++mul;
        }
        System.out.println(m - mp + 1);
    }
}