#include <bits/stdc++.h>
using namespace std;
typedef signed long long ll;

#define _P(...) (void)printf(__VA_ARGS__)
#define FOR(x,to) for(x=0;x<(to);x++)
#define FORR(x,arr) for(auto& x:arr)
#define FORR2(x,y,arr) for(auto& [x,y]:arr)
#define ALL(a) (a.begin()),(a.end())
#define ZERO(a) memset(a,0,sizeof(a))
#define MINUS(a) memset(a,0xff,sizeof(a))
template<class T> bool chmax(T &a, const T &b) { if(a<b){a=b;return 1;}return 0;}
template<class T> bool chmin(T &a, const T &b) { if(a>b){a=b;return 1;}return 0;}
//-------------------------------------------------------

int T,N,M;
int L[202020],R[202020];
ll num[202020];

ll ok(int v) {
	ll sum=0;
	int i;
	FOR(i,N) {
		if(v<L[i]) sum+=v;
		else sum+=min(R[i],v);
	}
	return M<=sum;
}

void solve() {
	int i,j,k,l,r,x,y; string s;
	
	cin>>T;
	while(T--) {
		cin>>N>>M;
		ll A=0,B=0;
		FOR(i,N) {
			cin>>L[i];
			A+=L[i];
		}
		FOR(i,N) {
			cin>>R[i];
			B+=R[i];
		}
		if(A>M||B<M) {
			cout<<-1<<endl;
			continue;
		}
		int cur=M;
		for(j=29;j>=0;j--) if(ok(cur-(1<<j))) cur-=1<<j;
		ll sum=0;
		FOR(i,N) {
			num[i]=min(max(L[i],cur-1),R[i]);
			sum+=num[i];
		}
		ll ret=0;
		FOR(i,N) {
			if(sum<M&&num[i]<R[i]) num[i]++, sum++;
			ret+=1LL*num[i]*(M-num[i]);
		}
		cout<<ret/2<<endl;
	}
}


int main(int argc,char** argv){
	string s;int i;
	if(argc==1) ios::sync_with_stdio(false), cin.tie(0);
	FOR(i,argc-1) s+=argv[i+1],s+='\n'; FOR(i,s.size()) ungetc(s[s.size()-1-i],stdin);
	cout.tie(0); solve(); return 0;
}