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.
from math import ceil


def log10(n):
    k = 0
    while 10 ** k <= n:
        k += 1
    return k


w, m, k = map(int, input().split())
d = 0
s = 0
n = m
while n:
    n //= 10
    d += 1
while True:
    r = log10(m)
    p = 10 ** r - m
    p *= d * k
    if w >= p:
        w -= p
        s += p // (d * k)
        m = 10 ** r
        d += 1
    else:
        s += w // (d * k)
        break
print(s)
