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


public class C371B {

	public static void main(String[] args) {
		
		Scanner sc = new Scanner(System.in);
		long ans = 0;
		long w = sc.nextLong();
		long m = sc.nextLong();
		long k = sc.nextLong();
		long count = Long.toString(m).length();
		long q = (long) (Math.pow(10, count) - 1);
		BigInteger end = new BigInteger(q + "");
		BigInteger ww = new BigInteger(w+"");
		BigInteger mm = new BigInteger(m+"");
		BigInteger kk = new BigInteger(k+"");
		if ((end.subtract(mm).add(new BigInteger(1+"")).multiply(new BigInteger(count+"").multiply(kk)).compareTo(ww)) > 0){
			ans += ww.divide(kk.multiply(new BigInteger(count+""))).longValue();
			System.out.println(ans);
			return;
		} else {
			ww = ww.subtract(kk.multiply(end.subtract(mm).add(new BigInteger("1"))).multiply(new BigInteger(count+"")));
			ans += end.subtract(mm).add(new BigInteger("1")).longValue();
		}
		while(true){
			count++;
			q = (long) (Math.pow(10, count) - Math.pow(10, count - 1)) ;
			end = new BigInteger(q + "");
			if((end.multiply(new BigInteger(count+"").multiply(kk))).compareTo(ww) > 0){
				ans += ww.divide(kk.multiply(new BigInteger(count+""))).longValue();
				break;
			} else {
				ww = ww.subtract(kk.multiply(end).multiply(new BigInteger(count+"")));
				ans += end.longValue();
			}
		}
		System.out.println(ans);
	}

}
