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.
w,m,k=map(int,input().split())
#print('w='+str(w)+' m='+str(m)+' k='+str(k))
n=m-1
l=len(str(m))
#print('l='+str(l))
while w>0:
    t=((10**l)-n-1)*l*k
    #print('t='+str(t))
    if w<=t:
        n+=w//(l*k)
        w=0
    else:
        n=10**l
        w=w-t-(l+1)*k
        l+=1
    #print('n='+str(n)+' w='+str(w))
print(n-m+1)
