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
#!/usr/bin/env python
# encoding: utf-8

line = raw_input();
ll = line.split();
w = long(ll[0])
m = long(ll[1])
k = long(ll[2])

#print "%d %d %d" % (w,m,k)
kk = w / k;

temp = 1L
cnt = 0L
ans = 0L

while(temp <= m):
    temp *= 10
    cnt += 1

cost = (temp - m) * cnt;
#print '%d %d' % (kk, cost)

while(kk >= cost):
    kk -= cost
    ans += (temp -m)
#    print "temp value %d" % ans
    m = temp
    temp *= 10
    cnt += 1
    cost = (temp - m) * cnt

if(cnt != 0):
    ans += kk / cnt

print ans


