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.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.util.StringTokenizer;

public class Task {
	public static void main(String[] args) {
		InputStream inputStream = System.in;
		OutputStream outputStream = System.out;
		InputReader in = new InputReader(inputStream);
		PrintWriter out = new PrintWriter(outputStream);
		TaskA s=new TaskA();
		s.solve(in, out);
		out.close();
	}
}

class TaskA {
	public void solve(InputReader in, PrintWriter out){
		long w=Long.parseLong(in.next());
		long m=Long.parseLong(in.next());
		long k=Long.parseLong(in.next());
		
		w/=k;
		k=1;
		
		long res=0;
		w+=f(m-1);
		int t=1;
		for(t=1;;t++){
			if(w==f(tenPow(t)-1)){
				res=tenPow(t)-1;
				break;
			}
			if(w<f(tenPow(t)-1))	
				break;
		}
		
		if(res==0){
			res=(w-f(tenPow(t-1)-1))/t+tenPow(t-1)-1;
		}
		out.println(res-m+1) ;
	}
	
	public long f(long a){
		int d=deep(a);
		long res=0;
		for(int i=1;i<d;i++){
			res+=i*(tenPow(i)-tenPow(i-1));
		}
		res+=d*(a-tenPow(d-1)+1);
		return res;
	}
	
	public int deep(long a){
		int res=1;
		while(a/10L!=0){
			a=a/10L;
			res++;
		}
		return res;
	}
	
	public long tenPow(int a){
		long res=1L;
		while(a>0){
			res*=10L;
			a--;
		}
		return res;
	}
}

class InputReader {
	private BufferedReader reader;
	private StringTokenizer tokenizer;

	public InputReader(InputStream stream) {
		reader = new BufferedReader(new InputStreamReader(stream));
		tokenizer = null;
	}

	public String next() {
		while (tokenizer == null || !tokenizer.hasMoreTokens()) {
			try {
				tokenizer = new StringTokenizer(reader.readLine());
			} catch (IOException e) {
				throw new RuntimeException(e);
			}
		}
		return tokenizer.nextToken();
	}

	public int nextInt() {
		return Integer.parseInt(next());
	}

}