Education

#include <bits/stdc++.h>
#define ll long long
#define ull unsigned long long int
#define ld long double
#define pb push_back
#define p_b pop_back
#define si stack<int>
#define sll stack<ll>
#define sc stack<char>
#define vi vector<int>
#define vll vector<ll>
#define mii map<int, int>
#define msi map<string, int>
#define mci map<char, int>
#define qc queue<char>
#define qi queue<int>
#define qll queue<ll>
using namespace std;

int main(){
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    int t;
    cin >> t;
    while(t--){
        int n;
        ll m;
        cin >> n >> m;
        ll a[n], b[n], dp[n] = {0}, tot = 0, count = 0;
        for(int i = 0; i < n; i++){
            cin >> a[i];
        }
        for(int i = 0; i < n-1; i++){
            cin >> b[i];
        }
        b[n-1] = 0;
        for(int i = 0; i < n; i++){
            dp[i] = count;
            dp[i] += ((m-tot)%a[i] == 0) ? (m-tot)/a[i] : (m-tot)/a[i]+1;
            ll cc = ((b[i]-tot)%a[i] == 0) ? (b[i]-tot)/a[i] : (b[i]-tot)/a[i]+1;
            if(tot >= b[i]){
                tot -= b[i];
                count++;
            } else{
                if(tot+a[i] > b[i]){
                    tot += a[i]-b[i];
                    count += 2;
                } else{
                    tot += cc*a[i]-b[i];
                    count += cc+1;
                }
            }
        }
        int min = dp[0];
        for(int i = 0; i < n; i++){
            if(dp[i] < min){
                min = dp[i];
            }
        }
        cout << min << "\n";
    }
    return 0;
}