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 B;

import java.math.BigInteger;
import java.util.Arrays;
import java.util.Scanner;

public class Main {
void run() {
	Scanner sc = new Scanner(System.in);
	BigInteger w,m,k,ans = BigInteger.ZERO;
	w = sc.nextBigInteger();
	m = sc.nextBigInteger();
	k = sc.nextBigInteger();
	int first = m.toString().length();
	for(int a=first;;a++){
		if(a==first){
			BigInteger cnt = BigInteger.valueOf(10).pow(first).subtract(m);
			BigInteger cost = cnt.multiply(k).multiply(BigInteger.valueOf(a));
			if(cost.compareTo(w) < 0){
				w = w.subtract(cost);
				ans = ans.add(cnt);
			} else {
				ans = ans.add(w.divide(BigInteger.valueOf(a).multiply(k)));
				break;
			}
		} else {
			BigInteger cnt = BigInteger.valueOf(10).pow(a).subtract(BigInteger.valueOf(10).pow(a-1));
			BigInteger cost = cnt.multiply(k).multiply(BigInteger.valueOf(a));
			if(cost.compareTo(w) < 0){
				w = w.subtract(cost);
				ans = ans.add(cnt);
			} else {
				ans = ans.add(w.divide(BigInteger.valueOf(a).multiply(k)));
				break;
			}
		}
	}
	System.out.println(ans.toString());

}

void debug(Object... o) {
	System.out.println(Arrays.deepToString(o));
}

public static void main(String[] args) {
	new Main().run();
}
}
