import sys

# sys.setrecursionlimit(200005)
# sys.set_int_max_str_digits(200005)
int1 = lambda x: int(x)-1
pDB = lambda *x: print(*x, end="\n", file=sys.stderr)
p2D = lambda x: print(*x, sep="\n", end="\n\n", file=sys.stderr)
def II(): return int(sys.stdin.readline())
def LI(): return list(map(int, sys.stdin.readline().split()))
def LLI(rows_number): return [LI() for _ in range(rows_number)]
def LI1(): return list(map(int1, sys.stdin.readline().split()))
def LLI1(rows_number): return [LI1() for _ in range(rows_number)]
def SI(): return sys.stdin.readline().rstrip()

dij = [(0, 1), (-1, 0), (0, -1), (1, 0)]
# dij = [(0, 1), (-1, 0), (0, -1), (1, 0), (1, 1), (1, -1), (-1, 1), (-1, -1)]
# inf = -1-(-1 << 31)
inf = -1-(-1 << 63)
# md = 10**9+7
md = 998244353

from heapq import *

def solve():
    def binary_search(l, r, minimize):
        if minimize: l -= 1
        else: r += 1
        while l+1 < r:
            m = (l+r)//2
            if ok(m) ^ minimize: l = m
            else: r = m
        if minimize: return r
        return l

    def ok(m):
        cnt = 0
        for l, r in zip(ll, rr):
            cnt += max(min(r, m), l)
            if cnt > M: return False
        return True

    n, M = LI()
    ll = LI()
    rr = LI()
    if sum(ll) > n or sum(rr) < n:
        print(-1)
        return
    x = binary_search(0, 10**9, False)
    # print(x)

    s = 0
    aa = []
    for l, r in zip(ll, rr):
        if l > x:
            aa.append(l)
            s += l
        elif r < x:
            aa.append(r)
            s += r
        else:
            aa.append(x)
            s += x

    d = M-s
    ans = 0
    for l, r, a in zip(ll, rr, aa):
        if a == x and d and r > a:
            a += 1
            d -= 1
        ans += (s-a)*a
    print(ans//2)

for _ in range(II()): solve()