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.
The first line contains three integers *w* (1 ≤ *w* ≤ 10<sup class="upper-index">16</sup>), *m* (1 ≤ *m* ≤ 10<sup class="upper-index">16</sup>), *k* (1 ≤ *k* ≤ 10<sup class="upper-index">9</sup>).

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.
import sys
import math
import collections
import heapq
input=sys.stdin.readline
w,m,k=(int(i) for i in input().split())
s=str(m)
c=0
while(w>0):
    n=len(s)
    s1=int('9'*n)
    k1=s1-m+1
    if(k1*n*k<=w):
        w-=k1*k
        c+=k1
        m=s1+1
        s=str(m)
    else:
        c+=(w//(n*k))
        w=0
print(c)