Sponsor’s Money#39
After two tournaments, in each of which the sponsor spent units of money, a new sponsor declared: "I will allocate more funds than both previous sponsors together." Every subsequent sponsor made the same statement.
Given the amount allocated by the first sponsor, the number of the upcoming tournament, and the amount in the sponsor's bank account, determine the maximum amount that may remain in the sponsor's account after sponsoring the -th tournament, or the amount they will have to borrow to cover the prizes.
The first line contains three numbers: , , (S \leq 1000, 0 < N \leq 1000, B \leq 10^{300}).
A single number — the amount remaining in the sponsor's account, or the amount they need to borrow.
Example 1