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.InputStreamReader;
import java.util.StringTokenizer;

public class CodeFoces_B_219 {

    public static void main(String[] args) throws IOException {
        BufferedReader bf = new BufferedReader(new InputStreamReader(System.in));
        StringTokenizer st = new StringTokenizer(bf.readLine());
        long w = Long.parseLong(st.nextToken());
        long m = Long.parseLong(st.nextToken());
        long k = Long.parseLong(st.nextToken());
        long sum = 0;
        String[] arr = new String[18];
        String s = "10";
        arr[0] = "0";
        for (int i = 1; i <= 17; i++) {
            arr[i] = s;
            s += "0";
        }

        for (int i = 1; i <= 17; i++) {
            if (m < Long.parseLong(arr[i])) {

                if (w <= 0) {
                    break;
                } else {
                    long canTake = w / (i * k);
                    long max=Long.parseLong(arr[i])-m;
                    if (canTake>max){
                        canTake=max;
                    }
                    w-=canTake*(i*k);   
                    
                    sum += canTake;
                    m+=canTake;
                    
                }
            }

        }
        System.out.println(sum);

    }
}
