A. Road To Zerotime limit per test1 secondmemory limit per test256 megabytesinputstandard inputoutputstandard outputYou are given two integers x and y. You can perform two types of operations:   Pay a dollars and increase or decrease any of these integers by 1. For example, if x = 0 and y = 7 there are four possible outcomes after this operation:   x = 0, y = 6;  x = 0, y = 8;  x = -1, y = 7;  x = 1, y = 7.   Pay b dollars and increase or decrease both integers by 1. For example, if x = 0 and y = 7 there are two possible outcomes after this operation:   x = -1, y = 6;  x = 1, y = 8.  Your goal is to make both given integers equal zero simultaneously, i.e. x = y = 0. There are no other requirements. In particular, it is possible to move from x=1, y=0 to x=y=0.Calculate the minimum amount of dollars you have to spend on it.InputThe first line contains one integer t (1 \le t \le 100) — the number of testcases.The first line of each test case contains two integers x and y (0 \le x, y \le 10^9).The second line of each test case contains two integers a and b (1 \le a, b \le 10^9).OutputFor each test case print one integer — the minimum amount of dollars you have to spend.ExampleInput
2
1 3
391 555
0 0
9 4
Output
1337
0
NoteIn the first test case you can perform the following sequence of operations: first, second, first. This way you spend 391 + 555 + 391 = 1337 dollars.In the second test case both integers are equal to zero initially, so you dont' have to spend money.
2
1 3
391 555
0 0
9 4

1337 0 
['greedy', 'math', '*1000']