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 nxt_num(n):
    return 10 ** len(str(n))


class CodeforcesTask373BSolution:
    def __init__(self):
        self.result = ''
        self.w_m_k = []

    def read_input(self):
        self.w_m_k = [int(x) for x in input().split(" ")]

    def process_task(self):
        k = self.w_m_k[2]
        budget = self.w_m_k[0]
        pos = self.w_m_k[1]
        length = 0
        while True:
            if (nxt_num(pos) - pos) * len(str(pos)) * k <= budget:
                budget -= (nxt_num(pos) - pos) * len(str(pos)) * k
                length += nxt_num(pos) - pos
                pos = nxt_num(pos)
            else:
                fin = budget // (len(str(pos)) * k)
                budget -= fin * (len(str(pos)) * k)
                length += fin
                break
        self.result = str(length)

    def get_result(self):
        return self.result


if __name__ == "__main__":
    Solution = CodeforcesTask373BSolution()
    Solution.read_input()
    Solution.process_task()
    print(Solution.get_result())
