B"You can perfectly predict the price of a certain stock for the next N days. You would like to profit on this knowledge, but only want to transact one share of stock per day. That is, each day you will either buy one share, sell one share, or do nothing. Initially you own zero shares, and you cannot sell shares when you don't own any. At the end of the N days you would like to again own zero shares, but want to have as much money as possible. Input begins with an integer N (2 xe2 x80 x89 xe2 x89 xa4 xe2 x80 x89N xe2 x80 x89 xe2 x89 xa4 xe2 x80 x893 xc2 xb7105), the number of days. Following this is a line with exactly N integers p1, xe2 x80 x89p2, xe2 x80 x89..., xe2 x80 x89pN (1 xe2 x80 x89 xe2 x89 xa4 xe2 x80 x89pi xe2 x80 x89 xe2 x89 xa4 xe2 x80 x89106). The price of one share of stock on the i-th day is given by pi. Print the maximum amount of money you can end up with at the end of N days. In the first example, buy a share at 5, buy another at 4, sell one at 9 and another at 12. Then buy at 2 and sell at 10. The total profit is xe2 x80 x89- xe2 x80 x895 xe2 x80 x89- xe2 x80 x894 xe2 x80 x89+ xe2 x80 x899 xe2 x80 x89+ xe2 x80 x8912 xe2 x80 x89- xe2 x80 x892 xe2 x80 x89+ xe2 x80 x8910 xe2 x80 x89= xe2 x80 x8920. "...