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.
p=input().split()
w=int(p[0])
m=int(p[1])
a=m
cost=int(p[2])
c=0
while(m!=0):
    m=m//10
    c=c+1
sum=0
x=10**c-a
if cost*c*x>=w:
    print(w//(cost*c))
else:
    sum=sum+x
    w=w-cost*c*x
    for i in range(c+1,18):
        y=9*(10**(i-1))
        if(y*i*cost>=w):
            break
        else:
            w=w-cost*y*i
            sum=sum+y
    print(sum+w//(cost*i))
        
