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.
def dcount(n):
    cnt=0;
    while n>0:
        n=int(n/10)
        cnt+=1
    return cnt


w=int(raw_input())
m=int(raw_input())
k=int(raw_input())
d=dcount(m)
ten=1
for i in range(d):
    ten*=10

cnt=0
while w>(ten-m)*d*k:
    cnt+=ten-m
    w-=(ten-m)*d*k
    d+=1
    m=ten
    ten*=10

cnt+=w/(d*k)
print cnt