A. Helmets in Night Lighttime limit per test1 secondmemory limit per test256 megabytesinputstandard inputoutputstandard outputPak Chanek is the chief of a village named Khuntien. On one night filled with lights, Pak Chanek has a sudden and important announcement that needs to be notified to all of the n residents in Khuntien.First, Pak Chanek shares the announcement directly to one or more residents with a cost of p for each person. After that, the residents can share the announcement to other residents using a magical helmet-shaped device. However, there is a cost for using the helmet-shaped device. For each i, if the i-th resident has got the announcement at least once (either directly from Pak Chanek or from another resident), he/she can share the announcement to at most a_i other residents with a cost of b_i for each share.If Pak Chanek can also control how the residents share the announcement to other residents, what is the minimum cost for Pak Chanek to notify all n residents of Khuntien about the announcement?InputEach test contains multiple test cases. The first line contains an integer t (1 \leq t \leq 10^4) — the number of test cases. The following lines contain the description of each test case.The first line contains two integers n and p (1 \leq n \leq 10^5; 1 \leq p \leq 10^5) — the number of residents and the cost for Pak Chanek to share the announcement directly to one resident.The second line contains n integers a_1,a_2,a_3,\ldots,a_n (1\leq a_i\leq10^5) — the maximum number of residents that each resident can share the announcement to.The third line contains n integers b_1,b_2,b_3,\ldots,b_n (1\leq b_i\leq10^5) — the cost for each resident to share the announcement to one other resident.It is guaranteed that the sum of n over all test cases does not exceed 10^5.OutputFor each test case, output a line containing an integer representing the minimum cost to notify all n residents of Khuntien about the announcement.ExampleInput
36 32 3 2 1 1 34 3 2 6 3 61 10000010000014 941 4 2 3103 96 86 57Output
16
100000
265
NoteIn the first test case, the following is a possible optimal strategy:   Pak Chanek shares the announcement directly to the 3-rd, 5-th, and 6-th resident. This requires a cost of p+p+p=3+3+3=9.  The 3-rd resident shares the announcement to the 1-st and 2-nd resident. This requires a cost of b_3+b_3=2+2=4.  The 2-nd resident shares the announcement to the 4-th resident. This requires a cost of b_2=3. The total cost is 9+4+3=16. It can be shown that there is no other strategy with a smaller cost.
36 32 3 2 1 1 34 3 2 6 3 61 10000010000014 941 4 2 3103 96 86 57
16 100000 265 
['greedy', 'sortings', '*1000']