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