Reference: Codeforces 865D — Buy Low Sell High

You know the price of one share of a certain stock for each of the next ~N~ days.

On each day, you may perform at most one of the following actions:

• buy one share;
• sell one share that you currently own;
• do nothing.

You initially own no shares. You may own several shares at the same time, but you may not sell a share unless you own at least one.

After the final day, you must own exactly zero shares.

Determine the maximum possible profit.

Input

• The first line contains one integer ~N~, the number of days.
• The second line contains ~N~ integers: ~p_1, p_2, \ldots, p_N~, where ~p_i~ is the stock price on day ~i~.

Output

• Print one integer: the maximum possible profit after all ~N~ days.

Constraints

• ~2 \le N \le 3 \times 10^5~
• ~1 \le p_i \le 10^6~

Example 1

Input:

9
10 5 4 7 9 12 6 2 10

Output:

20