Tanvir is on a quest to satisfy his shawarma cravings at the campus canteen. The canteen sells shawarmas at a regular price of \(p\) per item. However, they have two special offers:

• Offer 1: If a customer buys one shawarma, they receive a discount of \(a\) on the price.
• Offer 2: If a customer buys two shawarmas at once, they receive a discount of \(b\) on the price of two shawarmas.

However, Tanvir can only buy one or two shawarmas at a time.
You are given the regular price \(p\) of each shawarma and the total number of shawarmas \(n\)  Tanvir wants to buy. Help him calculate the minimum total price he needs to pay to satisfy his shawarma cravings.

The first line contains a single integer \(t\) — the number of test cases.
The first line of each test case contains four integers \(n, p, a, b\) — described in the statement.

\(1 \leq t \leq 10^5\)
\(1 \leq n \leq 10^5\)
\(2 \leq p \leq 10^4\)
\(1 \leq a < p\)
\(1 \leq b < 2 \cdot p\) 
It is guaranteed that the sum of \(n\) over all test cases doesn't exceed \(2 \cdot 10^5\).

For each test case, print a single integer — described in the statement.

Input copy	Output copy
2 3 20 3 5 5 20 3 10	51 77

In the first testcase of the sample, buying \(3\) times individually you will get \((20-3)*3=17*3=51\).