Solve the programming task below in a Python markdown code block.
Alice likes to shop online. The main reason is that she gets a lot of discounts! There are M online shops from where she purchases her items. The prices of the same item vary in both the shops. She needs to buy N items in all. And each she can buy each item in any one of the shops. All the shops offer certain discounts. If she buys the i^{th} item in one shop, she gets a discount coupon for the i+1^{th} item in the same shop. But if she purchases the i+1^{th} item from a different shop, she cannot use the discount coupon.
For example, if she buys the i^{th} item in Shop j and gets a discount of X rupees. Let the price of i+1^{th} item be Y rupees in shop j and Z rupees in shop k. If she purchases the i+1^{th} item from shop j she can use the discount coupon and hence, will have to pay Y-X rupees. If she purchases the i+1^{th} item from shop k she cannot use the discount coupon and hence, will have to pay Z rupees.
Note: If the discount given is more than price of the item in the shop, i.e. if Y-X < 0, the item is given free but she does NOT get any money back.
Alice wants to spend as less as possible and wants your help. She starts buying from item 1 and goes on till item N in that order. Your task is simple. Tell her the least amount to spend to get all the N items.

------ Input: ------ 

First line of input contains a single integer T, the number of test cases.

Each test case starts with a line consisting of two space separated integers N & M.
The next N lines consist of M space separated integers each. The j^{th} number on the i^{th} line denotes the price of i^{th} item in the j^{th} shop.

The next N lines consist of M space separated integers each. The j^{th} number on the i^{th} line denotes the value of discount coupon given after purchasing i^{th} item in the j^{th} shop.

------ Output: ------ 

For each test case, output on a separate line the least amount that has to be spent to get all the N items.

------ Constraints: ------ 

1 ≤ T ≤ 10
2 ≤ N, M ≤ 100000
0 ≤ Prices, Discounts ≤ 1000000
1 ≤ T * N * M ≤ 1000000

------ Scoring: ------ 

You will be awarded 40 points for solving the problem correctly for M = 2.

Another 20 points for solving the problem correctly for M ≤ 100.

Remaining 40 points will be awarded for solving the problem correctly for M > 100.

----- Sample Input 1 ------ 
2
2 2
3 4
1 2
1 0
0 1
2 4
1 2 3 4
4 3 2 1
2 3 2 1
1 2 1 1
----- Sample Output 1 ------ 
3
2