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 main():
    test()


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

    def s(n):
        return len(str(n))

    if s(m) * k > w:
        print(0)
        return

    def f(n):
        l = s(m)
        lm = s(m+n)
        if lm == l:
            return n * l * k
        sum = (10**l - m) * l * k
        sum += (m + n - 10**(lm-1) + 1) * lm * k
        for i in range(l + 1, lm):
            sum += i * (10**(i) - 10**(i-1) + 1) * k
        return sum

    a, b = 0, 10**16
    while (b-a) > 1:
        c = (a+b) // 2
        if f(c) <= w:
            a = c
        else:
            b = c
    print(a + 1)


main()
