Bizmarket

Bizmarket is an online general trading company that mainly serves businesses. It runs a welfare mall, corporate promotion and gift business, and industrial goods distribution. Beyond these core areas, it also runs brand, rental, and energy businesses. Its guiding principle is "contributing to the efficiency of client companies' operations and pursuing the welfare of their members." Shinuk was asked by Bizmarket to help run its rental business efficiently.

Bizmarket has $N$ items and $M$ client companies that want to rent them. Each item $i$ has a satisfaction value $A_i$, and each client company $j$ wants to rent an item by paying $B_j$. Each client company can rent only one item, and each item can be rented to only one client company.

If an item with satisfaction $A_i$ is rented to a client company that pays $B_j$, the client gains $A_i - B_j$ of client satisfaction. Every client company wants to get at least what it pays, so if the client satisfaction would drop below $0$, the company does not go through with the deal. Without a deal, no client satisfaction is gained.

Shinuk's task is to assign items to the client companies so that the total client satisfaction is maximized. He had too many assignments, so he handed this job to you and left. Compute the maximum total client satisfaction on his behalf.

The first line contains the integers $N$ and $M$, separated by a space. $(1 \le N, M \le 2 \times 10^5)$

The second line contains $N$ integers $A_1, A_2, \dots, A_N$, separated by spaces. $(0 \le A_i \le 10^9)$

The third line contains $M$ integers $B_1, B_2, \dots, B_M$, separated by spaces. $(0 \le B_j \le 10^9)$

On the first line, print the maximum total client satisfaction that can be obtained by choosing an item for each client company.

The answer can exceed the int range, so you must use a 64-bit integer type (C/C++: long long, Java: long).