CF385A Bear and Raspberry

The bear decided to store some raspberry for the winter. He cunningly found out the price for a barrel of honey in kilos of raspberry for each of the following $ n $ days. According to the bear's data, on the $ i $ -th $ (1

The first line contains two space-separated integers, $ n $ and $ c $ $ (2

Print a single integer — the answer to the problem.

In the first sample the bear will lend a honey barrel at day 3 and then sell it for 7. Then the bear will buy a barrel for 3 and return it to the friend. So, the profit is (7 - 3 - 1) = 3. In the second sample bear will lend a honey barrel at day 1 and then sell it for 100. Then the bear buy the barrel for 1 at the day 2. So, the profit is (100 - 1 - 2) = 97.