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 log10_(a):
    ans = 0
    while a//10:
        ans += 1
        a = a//10
    return ans

def pow10(a):
    ans = 1
    for i in range(a): ans *= 10
    return ans

w, m, k = [int(x) for x in input().split()]
ans = 0
costo = k*(log10_(m)+1)
for i in range(log10_(m)+1, 18):
    if (pow10(i)-m)*costo > w:
        ans += w//costo
        break
    w -= (pow10(i)-m)*costo
    ans += pow10(i)-m
    costo += k
    m = pow10(i)
print (ans)
	 			 				 	 			 		 	 	 	 				