B"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) xe2 x80 x89= xe2 x80 x893, S(114514) xe2 x80 x89= xe2 x80 x896. You want to make a consecutive integer sequence starting from number m (m, xe2 x80 x89m xe2 x80 x89+ xe2 x80 x891, xe2 x80 x89...). But you need to pay S(n) xc2 xb7k 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. The first line contains three integers w (1 xe2 x80 x89 xe2 x89 xa4 xe2 x80 x89w xe2 x80 x89 xe2 x89 xa4 xe2 x80 x891016), m (1 xe2 x80 x89 xe2 x89 xa4 xe2 x80 x89m xe2 x80 x89 xe2 x89 xa4 xe2 x80 x891016), k (1 xe2 x80 x89 xe2 x89 xa4 xe2 x80 x89k xe2 x80 x89 xe2 x89 xa4 xe2 x80 x89109). 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. The first line should contain a single integer -- the answer to the problem."...