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.*;

public class B {
    public static void main(String[] args) throws Exception {
        FastScannerB fs = new FastScannerB();
        PrintWriter out = new PrintWriter(System.out);
        Scanner s = new Scanner(System.in);

        long w = fs.nextLong(), start = fs.nextLong(), k = fs.nextLong();
        TreeSet<Long> pow = new TreeSet<>();
        for(long i = 10; i <= (long)1e18; i *= 10) pow.add(i);
        long res = 0, on = -1;
        boolean works = true;
        while(works) {
            long nextPow = pow.higher(start);
            long num = nextPow - start;
            long len = Long.toString(nextPow).length()-1;
            BigInteger price = BigInteger.valueOf(len).multiply(BigInteger.valueOf(num)).multiply(BigInteger.valueOf(k));
            //System.out.printf("At %d with %d and len %d with price %d and have %d\n", nextPow, num, len, price, w);
            if(price.compareTo(BigInteger.valueOf(w)) > 0) {
                works = false;
                on = nextPow;
            } else {
                w -= Long.parseLong(price.toString());
                res += num;
                start = nextPow;
            }
        }
        long lo = start, hi = on;
        long add = 0;
        //System.out.println("S " + start);
        for(int bs = 0; bs < 100; bs++) {
            long mid = (lo + hi) / 2;
            long num = mid - start;
            long len = Long.toString(mid).length();
            BigInteger price = BigInteger.valueOf(num).multiply(BigInteger.valueOf(len)).multiply(BigInteger.valueOf(k));
            //System.out.printf("At %d with %d and len %d with price %d and have %d\n", mid, num, len, price, w);
            if(price.compareTo(BigInteger.valueOf(w)) > 0) {
                //System.out.println("Bad");
                hi = mid-1;
            } else {
                //System.out.println("Good");
                add = Math.max(add, num);
                lo = mid+1;
            }
        }
        res += add;
        out.println(res);
        out.close();
    }
}
class FastScannerB {
    BufferedReader br;
    StringTokenizer st;

    public FastScannerB() {
        try	{
            br = new BufferedReader(new InputStreamReader(System.in));
            st = new StringTokenizer("");
        } catch (Exception e){e.printStackTrace();}
    }

    public String next() {
        if (st.hasMoreTokens())	return st.nextToken();
        try {st = new StringTokenizer(br.readLine());}
        catch (Exception e) {e.printStackTrace();}
        return st.nextToken();
    }

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

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

    public double nextDouble() {return Double.parseDouble(next());}

    public String nextLine() {
        String line = "";
        try {line = br.readLine();}
        catch (Exception e) {e.printStackTrace();}
        return line;
    }

    public Integer[] nextIntegerArray(int n) {
        Integer[] a = new Integer[n];
        for(int i = 0; i < n; i++) a[i] = nextInt();
        return a;
    }

    public int[] nextIntArray(int n) {
        int[] a = new int[n];
        for(int i = 0; i < n; i++) a[i] = nextInt();
        return a;
    }

    public char[] nextCharArray() {
        return next().toCharArray();
    }
}
