#include <bits/stdc++.h>
#include <atcoder/all>
#define SELECTER(_1,_2,_3,SELECT,...) SELECT
#define rep1(i,n) for(int i=0;i<(int)n;++i)
#define rep2(i,a,n) for(int i=(int)a;i<(int)n;++i)
#define rep(...) SELECTER(__VA_ARGS__,rep2,rep1)(__VA_ARGS__)
#define RSELECTER(_1, _2, _3, RSELECT, ...) RSELECT
#define rrep1(i,n) for(int i=(int)n-1;i>=0;--i)
#define rrep2(i,a,n) for(int i=(int)n-1;i>=(int)a;--i)
#define rrep(...) RSELECTER(__VA_ARGS__, rrep2, rrep1)(__VA_ARGS__)
#define all(a) a.begin(),a.end()
#define rall(a) a.rbegin(),a.rend()
#define fi first
#define se second
#define PrintR LogOutput
#ifdef _DEBUG
#define Log(...) LogOutput(__VA_ARGS__)
#else
#define Log(...)
#endif
using namespace std;
using namespace atcoder;
using ll=long long;
using ld=long double;
using pii=pair<int,int>;
using pll=pair<long long,long long>;
using pdd=pair<long double,long double>;
using tp=tuple<int,int,int>;
using tpll=tuple<ll,ll,ll>;
using veci=vector<int>;
using vecpii=vector<pair<int,int>>;
using vecll=vector<long long>;
using vecpll=vector<pair<long long,long long>>;
using vecpdd=vector<pair<long double,long double>>;
using vecs=vector<string>;
using vecb=vector<bool>;
using vecd=vector<long double>;
using vectp=vector<tp>;
using vectpll=vector<tpll>;
using mint=modint998244353;
using mint10=modint1000000007;
template<typename T, typename S>
istream& operator>>(istream& in, pair<T, S>& a){return in >> a.first >> a.second;}
template<typename T, typename S>
ostream& operator<<(ostream& out, const pair<T, S>& a){return out << a.first << ' ' << a.second;}
ostream& operator<<(ostream& out, const mint& a){return out << a.val();}
ostream& operator<<(ostream& out, const mint10& a){return out << a.val();}
ostream& operator<<(ostream& out, const modint& a){return out << a.val();}
template<typename T>
ostream& operator<<(ostream& out, const vector<T>& d){for(int i = 0 ; i < d.size() ; ++i) out << d[i] << (i == d.size() - 1 ? "" : " "); return out;}
template<typename T, typename S>
pair<T, S> operator+(const pair<T, S>& a, const pair<T, S>& b){return {a.fi + b.fi, a.se + b.se};}
template<typename T, typename S>
pair<T, S> operator-(const pair<T, S>& a, const pair<T, S>& b){return {a.fi - b.fi, a.se - b.se};}
template<class T> inline bool chmax(T& a,T b){if(a<b) {a=b;return true;} return false;}
template<class T> inline bool chmin(T& a,T b){if(a>b) {a=b;return true;} return false;}
bool Judge(int i, int j, int h, int w){return i < 0 || j < 0 || i >= h || j >= w;}
bool PrintA(int i){cout<<(i ? "Yes" : "No")<<endl;return i;}

constexpr ll INF=numeric_limits<ll>::max() / 4;
constexpr int inf=numeric_limits<int>::max() / 2;
constexpr ll MOD=998244353;
const int vi[] = {0, 1, 0, -1}, vj[] = {1, 0, -1, 0};

template<typename... Args>
void LogOutput(Args&&... args){
	stringstream ss;
	((ss << args << ' '), ...);
	cout << ss.str().substr(0, ss.str().length() - 1) << endl;
}
template<typename T>
void LogOutput(vector<vector<T>>& data){for(auto d : data) LogOutput(d);}

int main(){
	ios::sync_with_stdio(false);
	std::cin.tie(nullptr);
	int t;cin>>t;
	while(t--){
		int n, m;cin>>n>>m;
		veci a(n), b(n);
		rep(i, n) cin>>a[i];
		rep(i, n) cin>>b[i];
		ll s = 0, s2 = 0;
		ll ans = 0;
		priority_queue<pii, vecpii, greater<pii>> q;
		rrep(i, n){
			q.emplace(a[i], -i);
			q.emplace(b[i], i + 1);
			ans += s * a[i];
			s += a[i];
			s2 += b[i];
		}
		if(s > m || m > s2){
			cout<<-1<<endl;
			continue;
		}
		ll last = q.top().fi;
		q.pop();
		ll cnt = 1, remain = m - s;
		s -= last;
		while(q.size() && remain){
			auto [c, j] = q.top(); q.pop();
			int i = j;
			if(i > 0) --i;
			ll d = cnt * (cnt - 1) / 2;
			ll d2 = cnt * (cnt - 1);
			if(cnt * (c - last) <= remain){
				ans += s * cnt * (c - last);
				ans += (2 * d + d2 * (c - last - 1)) * (c - last) / 2;
				remain -= cnt * (c - last);
			}else if(cnt){
				ll u = remain / cnt;
				ll u2 = remain % cnt;
				ll d3 = d2 * (u - 1) + d;
				ans += (d + d3) * u / 2;
				if(u == 0) d3 = 0;
				ans += (d3 * 2 + (u2 - 1)) * u2 / 2;
				ans += s * remain;
				remain = 0;
			}
			s = s + last + (c - last) * cnt - c;
			last = c;
			if(j > 0) cnt--;
			else cnt++;
		}
		cout<<ans<<endl;
	}
}