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.
# your code goes here
w=(int)(input())
m=(int)(input())
k=(int)(input())
print(w,m,k)

ten=[]
power=[]
ten.append(0)
power.append(0)
ten.append(1)
power.append(9)
for x in range(1,30):
	ten.append(ten[len(ten)-1]*10)
	power.append(power[len(power)-1]*10+9)

cnt=0
foo=m


while(foo>0):
    cnt=cnt+1
    foo=foo//10


ini=m
end=power[cnt]
cost=0
cl=0

for x in range(cnt,20):
	lenght=end-ini+1
	cl+=lenght
	nc=lenght*x*k
	cost+=nc
	if cost>w :
		resp=w/(x*k)
		cost-=nc
		cost+=resp*x*k
		cl-=lenght
		cl+=resp
		break
	ini=ten[x+1]
	end=power[x+1]
	w-=nc
print(int(cl))
