#include <bits/stdc++.h>
#include <atcoder/all>
using namespace std;
using ll = long long;
#define rep(i,n) for(int i=0;i<(int)(n);i++)

void solve(){
	int n,m;
	cin>>n>>m;
	vector<ll> l(n),r(n);
	rep(i,n) cin>>l.at(i);
	rep(i,n) cin>>r.at(i);
	ll sml=0,smr=0;
	rep(i,n){
		sml+=l.at(i);
		smr+=r.at(i);
	}
	if(m<sml||smr<m){
		cout<<"-1\n";
		return;
	}
	ll up=m;
	ll dw=0;
	while(up-dw>1){
		ll md=(up+dw)/2;
		ll tmp=0;
		rep(i,n) tmp+=clamp(md,l.at(i),r.at(i));
		if(tmp>m) up=md;
		else dw=md;
	}
	vector<ll> v(n);
	rep(i,n){
		v.at(i)=clamp(dw,l.at(i),r.at(i));
		m-=v.at(i);
	}
	vector<int> p(n);
	rep(i,n) p.at(i)=i;
	sort(p.begin(),p.end(),[&](int i,int j){
		return v.at(i) < v.at(j);
	});
	for(int i:p){
		if(m<=0) break;
		if(v.at(i)+1<=r.at(i)){
			v.at(i)++;
			m--;
		}
	}
	reverse(v.begin(),v.end());
	ll sm=0;
	ll ans=0;
	rep(i,n){
		ans+=sm*v.at(i);
		sm+=v.at(i);
	}
	cout<<ans<<"\n";
}

int main(){
	int t;
	cin>>t;
	rep(i,t) solve();
}