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.

def sum(k):
    ret = 0
    pw = 10
    len = 1
    while 1 == 1:
        cur = min(pw - 1, k)
        prev = pw // 10
        ret += (cur - prev + 1) * len
        if (pw - 1 >= k):
            break
        len += 1
        pw *= 10
    return ret

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

lo = 0
hi = int(1e18)

while hi - lo > 1:
    md = (lo + hi) // 2
    c = sum(m + md - 1) - sum(m - 1)
    if c * k <= w:
        lo = md
    else:
        hi = md
print(lo)