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

i = 0
flag = 0
lenm = len(str(m))
nokori = 10**lenm-1 -(m-1)
if w - nokori*lenm*k > 0:
    while True:
        #print "y1"
        w = w - nokori*lenm*k
        #print "w",w
        lenm += 1
        nokori = 10**lenm-1 - (10**(lenm-1)-1)
        #print w-nokori*lenm*k
        if w - nokori*lenm*k <= 0:
            minl = 10**(lenm-1)
            minf = 10**(lenm-1)-1
            #print "in"
            break
elif w - nokori*lenm*k == 0:
    print nokori
    #print "y"
    flag = 1
else:
    minl = m
    minf = m-1
#print "out"
maxl = 10**lenm-1
#minl = 10**(lenm-1)
#minf = 10**(lenm-1)-1
#print "ugo"
while True:
    if flag == 1:break
    #print "y"
    x = (maxl+minl)/2
    #print "x",x
    #y = 
    a = w - (x-minf)*lenm*k
    #print "x,a",x,a,lenm
    if a > 0:
        if a < lenm*k:
            fix = x
            break
        elif a == lenm*k:
            fix = x+1
            break
        minl = x
    elif a < 0:
        if a > -lenm*k:
            fix = x-1
            break
        elif a == -lenm*k:
            fix = x-1
            break
        maxl = x
    elif a == 0:
        fix = x
        break
if not flag == 1:
    if fix >= m:
        print fix - m + 1
    else:
        print 0
