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 dcount(n):
    cnt=0;
    while n>0:
        n=int(n/10)
        cnt+=1
    return cnt


w,m,k=raw_input().split()
w=int(w)
m=int(m)
k=int(k)
d=dcount(m)
ten=1
for i in range(d):
    ten*=10

cnt=0
while w>(ten-m)*d*k:
    cnt+=ten-m
    w-=(ten-m)*d*k
    d+=1
    m=ten
    ten*=10

cnt+=w/(d*k)
print cnt