B"You are given two integers x and y . You can perform two types of operations: 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. The first line contains one integer t ( 1 <= t <= 100 ) -- the number of testcases. The first line of each test case contains two integers x and y ( 0 <= x, y <= 10^9 ). The second line of each test case contains two integers a and b ( 1 <= a, b <= 10^9 ). For each test case print one integer -- the minimum amount of dollars you have to spend. In 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. "...