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
r = lambda: map(int, raw_input().split())

w, m, k = r()
l, r = 0, 10 ** 17
nine = [10 ** i - 1 for i in xrange(1, 18)]
def check(cnt, w, m, k):
    upperbound = m + cnt - 1
    tot = 0
    for i, item in enumerate(nine):
        if item < m: continue
        if item <= upperbound:
            tot += (item - m + 1) * (i + 1) * k
            m = item + 1
        else:
            tot += (upperbound - m + 1) * (i + 1) * k 
            break
    # print tot
    return tot <= w

# check(7, w, m, k)    
while r > l:
    mid = (l + r + 1) >> 1
    if check(mid, w, m, k): l = mid
    else: r = mid - 1
print l