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.
ltab = [10**x for x in range(66)]

def S (num, start, end) :
    result = (start + end) // 2
    if num == ltab[result] :
        return result + 1
    elif num < ltab[result] and num >= ltab[result - 1]:
        return result
    elif num > ltab[result] and num < ltab[result + 1]:
        return result + 1
    elif num > ltab[result] :
        #print('find in [', result + 1, ', ', end, ']')
        return S(num, result + 1, end)
    else: # num < ltab[result] :
        #print('find in [', start, ', ', result - 1, ']')
        return S(num, start, result - 1)

w, m, k = map(int, input().split())
len = 0

while w >= 0 :
    t = S(m, 1, 64) * k
    if w < t:
        break;
    m += 1
    len += 1
    w -= t

print(len)
