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
//package proje;
import java.io.*;
import java.util.*;

public class m
{
	public static void main(String[] args) throws IOException
	{
		BufferedReader in;
		in = new BufferedReader(new InputStreamReader(System.in));
		BufferedWriter out;
		out=new BufferedWriter(new OutputStreamWriter(System.out));
		
		String h = in.readLine();
		String mkl[] = h.split(" ");
		
		long w = Long.parseLong(mkl[0]);
		long m = Long.parseLong(mkl[1]);
		
		long k = Long.parseLong(mkl[2]);
		
		int numod = mkl[1].length();
		
		long length=0;
		long currentposs = 1;
		String mjh="";
		for(int i=0; i<numod; i++)
		{
			if(i==0)
			{
				currentposs*=9;
				mjh+="1";
			}
			else
			{
				currentposs*=10;
				mjh+="0";
			}
		}
		long temp=m-Long.parseLong(mjh);
		//length=temp;
		long sum=0;
		//int flag=0;
		//if()
		while(true)
		{
			//System.out.println(w+" "+sum+" "+numod+" "+k);
			long len = (w-sum)/(numod*k);
			if(len>currentposs-temp)
			{
				//flag=1;
				length+=(currentposs-temp);
				sum+=(currentposs-temp)*numod*k;
			}
			else
			{
				length+=len;
				out.write((new Long(length)).toString());
				break;
			}
			temp=0;
			numod++;
			currentposs*=10;
		}
		
		out.flush();
		out.close();
	}
}