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
from sys import exit
line = raw_input()
#line = '10000000000000000 9999999999999999 1'
w, m, k = map(int, line.split())
l = len(str(m))
p = k * l
b = 10**(l-1)
n = 10**l-m
ans = 0

tmp = n*p
if w < tmp:
	tmp = w/p
	print tmp
	exit(0)
	
ans += n
w -= tmp
l += 1
p += k
b *= 10

while True:
	n = b * 9
	tmp = n * p
	if w < tmp:
		ans += w / p
		break
	ans += n
	w -= tmp
	l += 1
	p += k
	b *= 10
	
print ans
