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
import os,sys,math
###Making Sequences is Fun: 373B http://codeforces.com/problemset/problem/373/B 

###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, m, k

###output
#The first line should contain a single integer

def run():
    ###s(m) = log10(m) + 1
    w, m, k = map(int, raw_input().split())

    res = 0
    factor = 10
    s = 1
    while factor <= m:
        factor *= 10
        s += 1
    cur = m

    while w > 0:
        totalCost = (factor - cur) * s ##total cost for all numbers with same length of decimal base
        if totalCost*k <= w:
            res += totalCost / s
            w -= (k * totalCost)
            cur = factor
            s += 1
            factor *= 10
        else:
            res += w / k / s
            break
    print res
    return
################################################################################
run()
