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.math.BigInteger;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.HashMap;
import java.util.Scanner;
import java.util.StringTokenizer;

public class r219A {
    public static void main(String[] args) throws NumberFormatException,
            Exception {
        BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
        // Scanner k = new Scanner(System.in);

        // PrintWriter out = new PrintWriter(new
        // OutputStreamWriter(System.out));
        StringTokenizer s = new StringTokenizer(in.readLine());
        long w = Long.parseLong(s.nextToken());
        long m = Long.parseLong(s.nextToken());
        long k = Long.parseLong(s.nextToken());

        w /= k;
        double temp;
        int digit = (int) Math.ceil(temp = 1.0 * Math.log10(m));
        if (Double.compare(temp, (int) temp) == 0)
            digit++;

        BigInteger tens = BigInteger.TEN.pow(digit);
        BigInteger M = BigInteger.valueOf(m);
        long ans = 0;
        while (w > 0) {
            
            
            
            if(w/digit==0){
                break;
            }else{
                
                long n=tens.subtract(M).longValue();
                
                ans+=(n=Math.min(n,w/digit));
                w-=n*digit;
                M=new BigInteger(tens.toString());
                tens=tens.multiply(BigInteger.TEN);
                
            }
            digit++;
            
        }
        System.out.println(ans);

    }
}
