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.
read = lambda: tuple(map(int, input().split()))
w, m, k = read()
l = [10**v-1 for v in range(1, 17)]
cv = m
s = lambda v: len(str(v))*k
cd = 0
ln = 0
for lv in l:
    if cv < lv:
        d = min(w, (lv - cv + 1) * s(cv)) // s(cv)
        w -= d * s(cv)
        ln += d
        cv = lv + 1
        
        
        
print(ln)
