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 math import log10
[w, m, k] = [int(i) for i in raw_input().split(" ")]
digits = w / k
# print "accept {digits}".format(digits = digits)
step = None
totalStep = 0
currentStep = int(log10(m)) + 1
movable = 10 ** currentStep - m
# print step, currentStep, movable
if digits > 0:
    while digits >= 0 and step != 0:
        step = min(movable, digits / currentStep)
        totalStep += step
        # print "step :" + str(step)
        digits -= step * currentStep
        # print "digits :" + str(digits)
        m += step
        # print "m:" + str(m)
        currentStep = int(log10(m)) + 1
        movable = 10 ** currentStep - m
        # print step, currentStep, movable, totalStep

else:
    step  = 0
    totalStep = 0

print totalStep