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.
int_in = input()
integers = int_in.split()
integers = list(map(int, integers))
w = integers[0]
m = integers[1]
k = integers[2]

n = 0

while (10 ** n) <= m:
    n += 1

max_len = 10 ** (n) - m
c = (10 ** (n) - m) * n * k
m = 10 ** n
n += 1

while c + (10 ** (n) - m) * n * k <= w:
    c += (10 ** (n) - m) * n * k
    max_len += 10 ** (n) - m
    m = 10 ** n
    n += 1
max_len += (w - c) // (n * k)

print(max_len)
		 	   		 			 		 	   			  	   	