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 CodeForces373B {

	public static int countDigits(long num) {
		int ans = 0;
		while (num > 0) {
			num /= 10;
			ans++;
		}	
		return ans;
	}

	public static void main(String[] args) {
		Scanner input = new Scanner(System.in);

		long w = input.nextLong();
		long m = input.nextLong();
		long k = input.nextLong();
		
		BigInteger wBI = new BigInteger("" + w);
		BigInteger mBI = new BigInteger("" + m);
		BigInteger kBI = new BigInteger("" + k);
		
		BigInteger curBI = new BigInteger("" + m); // a copy of mBI
		
		while (w > 0) {

			BigInteger d = new BigInteger("" + curBI.toString().length());
			BigInteger singleCost = d.multiply(kBI); // cost of writing down a single number with length d
			
			// count of all numbers with length d that are at least as large as curBI
			BigInteger remainingNumAtCostLevel = BigInteger.TEN.pow((int) d.longValue()).subtract(curBI); 
			
			// cost of writing down all numbers with length d, starting from curBI
			BigInteger bulkCost = singleCost.multiply(remainingNumAtCostLevel);
						
			if (bulkCost.compareTo(wBI) <= 0) {
				// can afford writing down all numbers of length d, starting from curBI inclusive
				wBI = wBI.subtract(bulkCost);
				curBI = curBI.add(remainingNumAtCostLevel);
			} else {
				// can't afford it, add the count of how many numbers of length d we can write down (starting from curBI inclusive)
				curBI = curBI.add(wBI.divide(singleCost));						
				break;
			}

		}
		
		System.out.println(curBI.subtract(mBI));
		input.close();
	}

}
