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
def dig(x):
	ct=0
	while(x!=0):
		x/=10;
		ct=ct+1
	return ct;
def next1(x):
	if(x==0):
		return 1
	a=10;
	for i in range(1,x):
		a*=10
	return a

s=raw_input();
x=s.split(' ')
w=int(x[0])
m=int(x[1])
k=int(x[2])
ans=0
while w>0:
	digits=dig(m)
	diff=next1(digits)-m
	if((diff*digits*k)<=w):
		ans+=diff
		w-=(diff*digits*k);
	else:
		x=w/(k*digits);
		ans+=x;
                w-=(x*digits*k);
		break;
	m=next1(digits)
print ans
