import bisect

def main():
    n_tests = int(input())

    for _ in range(n_tests):
        n, m = [int(i) for i in input().split()]
        ai = [int(i) for i in input().split()]
        bj = [int(i) for i in input().split()]

        ai.sort()

        for i in range(m):
            tmp = ai.pop(0)
            bisect.insort(ai, bj[i])

        print(sum(ai))

main()