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 findten(x):
    ans = 1
    while ans <= x:
        ans *= 10
    return ans

def s(x):
    ans = 0
    while x:
        ans += 1
        x //= 10
    return ans


w, m, k = (int(i) for i in input().split())

ans = 0
p = findten(m)

while w > 0:
    temp = s(m) * k * (p - m)
    if w - temp >= 0:
        ans += (p - m)
        m = p
        p *= 10
        w -= temp
    else:
        t = w // (s(m) * k)
        ans += t
        break

print(ans)
