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.
The first line contains three integers *w* (1 ≤ *w* ≤ 10<sup class="upper-index">16</sup>), *m* (1 ≤ *m* ≤ 10<sup class="upper-index">16</sup>), *k* (1 ≤ *k* ≤ 10<sup class="upper-index">9</sup>).

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.
import math


def length(x):
    if x == 0:
        return 1
    return math.floor(math.log(x, 10)) + 1


w, m, k = map(int, input().split())
m -= 1

power = 10 ** length(m)
ans = 0
l = length(m)

while w > 0:
    num = power - m - 1

    if l * k * num <= w:
        w -= l * k * num
        ans += num
    else:
        ans += w // (l * k)
        w = 0
    m = power
    power *= 10
    l += 1

print(ans)

