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

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

d_m = s(m)
c=0

while( (w-(10**d_m - m)*d_m*k) >= 0):
	w = w - (10**d_m - m)*d_m*k
	c += d_m*(10**d_m - m)
	m = 10**(d_m)
	d_m += 1

while( w - s(m)*k>=0):
	w = w -s(m)*k
	c = c + 1 
	m = m + 1

print(c)
       	 	 		    	  	  	 			  	