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


public class MakingSequencesIsFun {
	static long w;
	static long m;
	static long k;
	public static void main(String[] args) throws Exception{
		Scanner sc = new Scanner(System.in);
		PrintWriter out = new PrintWriter(System.out);
		
		w = sc.nextLong();
		m = sc.nextLong();
		k = sc.nextLong();
		
		long curnum = m;
		long remCredit = w;
		
		while(true) {
			long next = max(countDig(curnum));
			BigInteger curCost = cost(curnum, next);
			if(curCost.compareTo(BigInteger.valueOf(remCredit)) <= 0) {
				remCredit-=curCost.longValue();
				curnum = next+1;
			} else {
				break;
			}
		}
		
		long nums = remCredit / (countDig(curnum) * k);
		out.println(nums - m + curnum);
		out.close();
	}
	
	// must have same digs
	static BigInteger cost(long start, long end) {
		return BigInteger.valueOf(end - start + 1).multiply(BigInteger.valueOf(countDig(start))).multiply(BigInteger.valueOf(k));
	}
	
	static long max(long countDig) {
		return (long) (Math.pow(10, countDig) - 1);
	}
	
	static long countDig(long x){
		long dig = 0;
		while(x>0){
			dig++;
			x/=10;
		}
		return dig;
	}
}
