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
def val(n,k) :
   pow10 = 1
   cnt = 0
   ans = 0
   len = 1
   while(pow10 * 10 <= n) :
      cnt = pow10 * 9
      ans += len * cnt * k;
      pow10 *= 10
      len += 1

   m = n - pow10 + 1
   ans += m * k * len
   return ans;


w,m,k = map(int,raw_input().split())

lo = 0
hi = 10**18
mcnt = val(m-1,k)

while (hi - lo > 1):
   mid = (lo + hi)/2
   if(val(mid,k) <= mcnt + w):
      lo = mid
   else:
      hi = mid
 
if(lo < m): print 0
else: print (lo - m + 1)
