import sys
input = sys.stdin.readline

T=int(input())
for tests in range(T):
    n,m=map(int,input().split())
    L=list(map(int,input().split()))
    R=list(map(int,input().split()))

    if sum(L)<=m<=sum(R):
        pass
    else:
        print(-1)
        continue

    OK=0
    NG=10**9+1

    while OK+1<NG:
        mid=(OK+NG)//2

        count=0
        for i in range(n):
            if L[i]<=mid:
                count+=min(mid,R[i])
            else:
                count+=L[i]

        if count<=m:
            OK=mid
        else:
            NG=mid

    #print(OK)

    rest=m
    KO=[0]*n
    CAN=[]

    for i in range(n):
        if L[i]<=OK:
            x=min(OK,R[i])
        else:
            x=L[i]
            
        KO[i]=x
        rest-=x

        if x==OK and x<R[i]:
            CAN.append(i)

    for j in range(rest):
        KO[CAN[j]]+=1

    #assert sum(KO)==m

    #for i in range(n):
    #    assert L[i]<=KO[i]
    #    assert KO[i]<=R[i]

    #print(KO)

    SUM=0
    ANS=0
    for ko in KO:
        ANS+=SUM*ko
        SUM+=ko

    print(ANS)