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.
pow10 = [10**i for i in range(20)]
w, m, k = map(int, input().split())
x = 1
while (m > pow10[x]): x += 1
if (pow10[x] - m) * x * k >= w:
    print((w) // (x * k))
    exit()
cur = (pow10[x] - m) * x * k
tmp = pow10[x] - m
while (cur + (9 * pow10[x]) * (x+1) * k <= w):
    x += 1
    cur += (9 * pow10[x - 1]) * x * k
    tmp += 9 * pow10[x - 1]
print(tmp + (w - cur) // (x * k))
