373_B. Making Sequences is Fun
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.

Input

The first line contains three integers w (1 ≤ w ≤ 1016), m (1 ≤ m ≤ 1016), k (1 ≤ k ≤ 109).

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.

Output

The first line should contain a single integer — the answer to the problem.

Examples

Input

9 1 1


Output

9


Input

77 7 7


Output

7


Input

114 5 14


Output

6


Input

1 1 2


Output

0
```python
from math import *

w, m, k = list(map(int, input().split()))
cnt = 0
add = 9*10**(-1) if m < 10 else 0
for i in range(int(log10(m)), int(1e10)):
    v = (9 * 10**i - (m-1-9*10**(i-1)+add if i == int(log10(m)) else 0)) * (i+1) * k
    if w - v < 0:
        cnt += w//((i+1)*k)
        break
    w -= v
    cnt += v//(k*(i+1))
print(int(cnt))

```