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
import math

def cal(num):
    start = 1
    end = num
    sum = 0
    num_digits = 1
    while (start <= end):
        end_range = min((start*10) -1,end)
        sum += ((end_range - start + 1) * num_digits)

        start = end_range + 1
        num_digits += 1
    return sum

def bin_search(left, right, max_sum):
    middle = left + ((right - left) / 2)
    middle_cal = cal(middle)
    middle_plus_one_cal = cal(middle + 1)
    if middle_cal <= max_sum and middle_plus_one_cal > max_sum:
        return middle
    if middle_cal <= max_sum and  middle_plus_one_cal <= max_sum:
        return bin_search(middle + 1, right, max_sum)
    return bin_search(left, middle - 1, max_sum)


def get_seq_max_length(w,m,k):
    if w < int((math.log(m,10) + 1)) * k:
        return 0
    max_sum = w/k
    ans = bin_search(1, 2*pow(10,16), max_sum + cal(m-1))
    return (ans - m + 1)

nums = map(int, raw_input('').split())
print get_seq_max_length(*nums)
    
