from sys import stdin
input = stdin.readline

def func(limit):
    SUM = 0
    for i in range(N):
        if limit < L[i]:
            SUM += L[i]
        elif R[i] < limit:
            SUM += R[i]
        else:
            SUM += limit
    return SUM

for _ in range(int(input())):
    N, M = map(int, input().split())
    L = list(map(int, input().split()))
    R = list(map(int, input().split()))

    if M < sum(L) or sum(R) < M:
        print(-1)
        continue

    left = 0
    right = 10**9+1
    while left+1 < right:
        mid = (left+right)//2
        if func(mid) <= M:
            left = mid
        else:
            right = mid
    
    C = [0]*N
    for i in range(N):
        if left < L[i]:
            C[i] = L[i]
        elif R[i] < left:
            C[i] = R[i]
        else:
            C[i] = left
    rem = M-sum(C)
    for i in range(N):
        if rem == 0: break
        if C[i] == left and C[i] < R[i]:
            C[i] += 1
            rem -= 1
    
    print((M*M-sum(c*c for c in C))//2)