Codeforces Round #219 (Div. 2) B. Making Sequences is Fun

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,?...

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 payS(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.