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(n):
    len(str(n))

def solve():
    w, m, k = map(int, raw_input().split())
    ret = 0
    while w > 0:
        nm = (10**len(str(m)) - m)
        if w >= nm*k*len(str(m)):
            w -= nm*k*len(str(m))
            ret += nm
            m = 10**len(str(m))
        else:
            l = 0
            r = 10**len(str(m))
            while(r - l > 1):
                t = (r + l) / 2
                if w >= t*k*len(str(m)):
                    l = t
                else:
                    r = t
            ret += l
            print ret
            return
    print ret
    return

            

if __name__ == "__main__":
    solve()

