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 dec_len(n):
    s=str(n)
    return len(s)

def last(mx,m,k):
    return mx-(mx-m)%k

def quanto(m,st):
    mx=int(10**st)
    cl=mx-m
    m=mx
    return cl,m
        

w,m,k=map(int,input().split(' '))

d=0

while 1:
    l=dec_len(m)
    cl,nm=quanto(m,l)
    #print('cl={} nm={} w={}'.format(cl,nm,w))
    if w>cl*k*l:
        w-=cl*k*l
        d+=cl
    else:
        cl=w//(k*l)
        d+=cl
        break
    m=nm
    
print(d)

