from heapq import heappush, heappop

T = int(input())
for _ in range(T):
  n, m = map(int, input().split())
  L = list(map(int, input().split()))
  R = list(map(int, input().split()))
  ttl = sum(L)
  if m < ttl or sum(R) < m:
    print(-1)
    continue
  
  que = []
  for i in range(n):
    if L[i] < R[i]:
      heappush(que, (L[i], i))
  while ttl < m:
    l, i = heappop(que)
    L[i] += 1
    ttl += 1
    if L[i] < R[i]:
      heappush(que, (L[i], i))
  ans = sum(l * (m - l) for l in L) // 2
  print(ans)