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 s(n):
	#digits = 0
	#while n>0 :
	#	digits += 1
	#	n=n//10
	#return digits
	return len(str(n))

entrada = input()
lista_entrada = entrada.split()
w = int(lista_entrada[0])
m = int(lista_entrada[1])
k = int(lista_entrada[2])

l=list()
#while(w-s(m)*k): ¿?

while(w-s(m)*k>=0):
	w = w - s(m)*k
	l.append(m)
	m = m + 1

print(len(l))
   			  		 	 	   	      			 	 	