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.

Input

The first line contains three integers w (1 ≤ w ≤ 1016), m (1 ≤ m ≤ 1016), k (1 ≤ k ≤ 109).

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.

Output

The first line should contain a single integer — the answer to the problem.

Examples

Input

9 1 1


Output

9


Input

77 7 7


Output

7


Input

114 5 14


Output

6


Input

1 1 2


Output

0
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())
