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.util.*;
import java.io.*;
public class Main {
    static BufferedReader reader 
		= new BufferedReader(new InputStreamReader(System.in));       

    public static void main(String[] args){
        long[] inp = nextLongArray();
        long w = inp[0];
        long m = inp[1];
        long k = inp[2];
        w = w / k;
        long cnt = 0; // this is the answer
        while (true) {
            long tmp = ((long) Math.pow(10, s(m)) - m) * s(m);
            if (tmp > w){
                System.out.println((long) (0.0000001 + (double) w / s(m)) + cnt);
                return;
            } else {
                w -= tmp;
                cnt += (long) (0.00001 + Math.pow(10, s(m))) - m;
                m = (long) (0.000001 + Math.pow(10, s(m)));
            }
        }
    }
    static int s(long n){
        return ("" + n).length();
    }

    static int nextInt(){
        return Integer.parseInt(nextLine());
    }
    static int nextLong(){
        return Integer.parseInt(nextLine());
    }
    static int[] nextIntArray(){
        String[] inp = nextLine().split("\\s+");
        int[] ary = new int[inp.length]; for (int i = 0; i < ary.length; i++){
            ary[i] = Integer.parseInt(inp[i]);
        }
        return ary;
    }
    static int[] nextIntArrayFrom1(){
        String[] inp = nextLine().split("\\s+");
        int[] ary = new int[inp.length + 1];
        for (int i = 0; i < inp.length; i++){
            ary[i+1] = Integer.parseInt(inp[i]);
        }
        return ary;
    }
    static long[] nextLongArray(){
        String[] inp = nextLine().split("\\s+");
        long[] ary = new long[inp.length];
        for (int i = 0; i < inp.length; i++){
            ary[i] = Long.parseLong(inp[i]);
        }
        return ary;
    }
    static long[] nextLongArrayFrom1(){
        String[] inp = nextLine().split("\\s+");
        long[] ary = new long[inp.length + 1];
        for (int i = 0; i < inp.length; i++){
            ary[i+1] = Long.parseLong(inp[i]);
        }
        return ary;
    }
	static String nextLine(){
		try { 
			return reader.readLine().trim();
		} catch (Exception e){}
		return null;
	}
}

