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
def main():
	[w,m,k] = map(int,raw_input().split(' '))
	n = 0
	# w < 10^16 , m < 10^16 , k < 10^9
	wt = [9, 90, 900, 9000, 90000, 900000, 
		  9000000, 90000000, 900000000, 9000000000, 
		  90000000000, 900000000000, 9000000000000, 
		  90000000000000, 900000000000000, 9000000000000000, 
		  90000000000000000]
	i = 0
	p = m
	while p:
		p = p//10
		i += 1 
	i -= 1
	wt[i] = 10**(i+1) - m 

	while w >= 0 and i<17:
		z = wt[i]*k*(i+1)
		if w >= z:
			w -= z
			n += wt[i]
		else:
			n += w//(k*(i+1))
			w = 0
		i+=1
	print n
main()
