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
from Queue import * # Queue, LifoQueue, PriorityQueue
from bisect import * #bisect, insort
from datetime import * 
from collections import * #deque, Counter,OrderedDict,defaultdict
import calendar
import heapq
import math
import copy
import itertools
myread = lambda : map(int,raw_input().split())

def OK(n,m,w,k):
    max_num = n + m - 1
    len_m = len(str(m))
    len_max = len(str(max_num))

    if len_m == len_max:
        ans = ((max_num - m) + 1) * len_m * k
    else:
        ans = ((10 ** (len_m) - m)) * len_m * k
        for i in range(len_m,len_max-1):
            ans += 9 * (10 ** i) * (i+1) * k
            
        ans += (max_num - (10 ** (len_max - 1)) + 1) * len_max * k

    return ans <= w
    


def solver():
    w,m,k = raw_input().split()
    w = int(w)
    k = int(k)
    m = int(m)

    lp = 0
    up = 10 ** 16 + 100

    while lp != up:
        mid = (lp + up) / 2 + 1
        
        if OK(mid,m,w,k):
            lp = mid
        else:
            up = mid - 1
        

    print lp

    









if __name__ == "__main__":
    solver()
    
