#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
template<class T>bool chmax(T &a, const T &b) { if (a<b) { a=b; return true; } return false; }
template<class T>bool chmin(T &a, const T &b) { if (b<a) { a=b; return true; } return false; }
#define all(x) (x).begin(),(x).end()
#define fi first
#define se second
#define mp make_pair
#define si(x) int(x.size())
const int mod=998244353,MAX=300005,INF=1<<30;

int main(){
    
    std::ifstream in("text.txt");
    std::cin.rdbuf(in.rdbuf());
    cin.tie(0);
    ios::sync_with_stdio(false);
    
    int Q;cin>>Q;
    while(Q--){
        ll N,M;cin>>N>>M;
        vector<ll> L(N),R(N);
        ll lsum=0,rsum=0;
        for(int i=0;i<N;i++) cin>>L[i];
        for(int i=0;i<N;i++) cin>>R[i];
        
        for(int i=0;i<N;i++){
            lsum+=L[i];
            rsum+=R[i];
        }
        
        if(M<lsum||rsum<M){
            cout<<-1<<"\n";
            continue;
        }
        
        ll left=0,right=1.5e9;
        
        while(right-left>1){
            ll mid=(left+right)/2;
            ll sum=0;
            for(int i=0;i<N;i++){
                if(mid<L[i]) sum+=L[i];
                else sum+=min(mid,R[i]);
            }
            
            if(sum<=M) left=mid;
            else right=mid;
        }
        
        vector<ll> ans(N);
        ll sum=0;
        ll mid=left;
        for(int i=0;i<N;i++){
            if(mid<L[i]) ans[i]=L[i];
            else ans[i]=min(mid,R[i]);
            
            sum+=ans[i];
        }
        
        for(int i=0;i<N;i++){
            if(sum+1<=M){
                if(mid<L[i]){
                    
                }else if(mid+1<=R[i]){
                    sum++;
                    ans[i]++;
                }
            }
        }
        
        ll res=M*(M-1)/2;
        for(ll a:ans) res-=a*(a-1)/2;
        
        cout<<res<<"\n";
    }
}