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

/**
 * Built using CHelper plug-in
 * Actual solution is at the top
 */
public class Main {
	public static void main(String[] args) {
		InputStream inputStream = System.in;
		OutputStream outputStream = System.out;
		InputReader in = new InputReader(inputStream);
		PrintWriter out = new PrintWriter(outputStream);
		TaskB solver = new TaskB();
		solver.solve(1, in, out);
		out.close();
	}
}

class TaskB {
    public void solve(int testNumber, InputReader in, PrintWriter out) {
        long w = in.nextLong();
        long m = in.nextLong();
        long k = in.nextInt();
        int i = (m+ "").length();
        long weights = 0;
        long ans = 0;
        while (true) {
            long no  = 9;
            long sub = 1;
            for(int j =0;j<i-1;j++){
                no *= 10;
                if(weights == 0) sub *= 10;
            }

            no -= m - sub;
            //ans += no;
            m = 1;
            BigInteger ww = BigInteger.valueOf(weights);
            if(ww.add(BigInteger.valueOf(no).multiply(BigInteger.valueOf(k)).multiply(BigInteger.valueOf(i))).compareTo(BigInteger.valueOf(w))<0/*weights + no*k*i < w*/) {
                weights += (no)*k*i;
                ans += no;
            }
            else {
                long v = w - weights;
                long aa = v/(i*k);
                ans += aa;
                break;
            }
            i++;
        }
        out.println(ans);

    }
}

class InputReader {
    private BufferedReader br;
    private StringTokenizer st;
    public InputReader(InputStream in) {
        br=new BufferedReader(new InputStreamReader(in));
        try {
            st=new StringTokenizer(br.readLine());
        } catch (IOException ignored) {

        }
    }

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

    public long nextLong(){
        return Long.parseLong(st.nextToken());
    }



}
