import sys, random
input = lambda : sys.stdin.readline().rstrip()


write = lambda x: sys.stdout.write(x+"\n"); writef = lambda x: print("{:.12f}".format(x))
debug = lambda x: sys.stderr.write(x+"\n")
YES="Yes"; NO="No"; pans = lambda v: print(YES if v else NO); INF=10**18
LI = lambda : list(map(int, input().split())); II=lambda : int(input()); SI=lambda : [ord(c)-ord("a") for c in input()]
def debug(_l_):
    for s in _l_.split():
        print(f"{s}={eval(s)}", end=" ")
    print()
def dlist(*l, fill=0):
    if len(l)==1:
        return [fill]*l[0]
    ll = l[1:]
    return [dlist(*ll, fill=fill) for _ in range(l[0])]

t = II()
for _ in range(t):
    n,m = list(map(int, input().split()))
    ls = LI()
    rs = LI()
    sl = sum(ls)
    sr = sum(rs)
    if sl<=m<=sr:
        es = []
        for i in range(n):
            es.append((ls[i],i,1))
            es.append((rs[i],i,-1))
        es.sort()
        size = 0
        cur = sl
        # val = sum([v*v for v in ls])
        val = 0
        p = es[0][0]
        if cur<m:
            for v,i,e in es:
                # size 個が p -> v になろうとする
                if v>p:
                    if cur + size*(v-p) >= m:
                        dd,mm = divmod(m - cur, size)
                        # size-mm個が +dd, mm個が+dd+1
                        val += (size-mm) * (2*dd*p+dd*dd) + mm * (2*(dd+1)*p+(dd+1)*(dd+1))
                        break
                    val += size * (v*v - p*p)
                    cur += size * (v-p)
                size += e
                p = v
        val += sum([v*v for v in ls])
        ans = (m*m - val)//2
    else:
        ans = -1
    print(ans)
#     break