A - Cake

#include <bits/stdc++.h>
using namespace std;

#define cin(vec) for(auto& i : vec) cin >> i
#define cin_2d(vec, n, m) for(int i = 0; i < n; i++) for(int j = 0; j < m && cin >> vec[i][j]; j++);
#define cout(vec) for(auto& i : vec) cout << i << " "; cout << "\n";
#define cout_2d(vec, n, m) for(int i = 0; i < n; i++, cout << "\n") for(int j = 0; j < m && cout << vec[i][j] << " "; j++);
#define cout_map(mp) for(auto& [f, s] : mp) cout << f << "  " << s << "\n";
#define Time cerr << "Time Taken: " << (float)clock() / CLOCKS_PER_SEC << " Secs" << "\n";
#define fixed(n) fixed << setprecision(n)
#define ceil(n, m) (((n) / (m)) + ((n) % (m) ? 1 : 0))
#define fill(vec, value) memset(vec, value, sizeof(vec));
#define Num_of_Digits(n) ((int)log10(n)+1)
#define mod_combine(a, b, m) (((a % m) * (b % m)) % m)
#define all(vec) vec.begin(),vec.end()
#define rall(vec) vec.rbegin(),vec.rend()
#define sz(x) int(x.size())
#define TC int t; cin >> t;   while(t--)
#define fi first
#define se second
#define Pair pair < int, int >
#define ll long long
#define ull unsigned long long
#define Mod  1'000'000'007
#define OO 2'000'000'000
#define EPS 1e-9
#define PI acos(-1)

void AhMeD_HoSSaM(){
  ios_base::sync_with_stdio(false), cin.tie(nullptr), cout.tie(nullptr);
  #ifndef ONLINE_JUDGE
    freopen("input.txt", "r", stdin), freopen("output.txt", "w", stdout);
  #endif
  freopen("cakes.in", "r", stdin);
}

int main(){
  AhMeD_HoSSaM();
  TC {
    ll n, m, curr_cost = 0, Max_Cakes = -OO;
    cin >> n >> m;
    vector < pair < ll, ll > > cakes(n);
    for(auto& [x, t] : cakes) cin >> x;
    for(auto& [x, t] : cakes) cin >> t;
    sort(all(cakes));
    priority_queue < ll > cost;
    for(int i = 0; i < n; i++){
      ll rem = m - cakes[i].fi;
      cost.push(cakes[i].se);
      curr_cost += cakes[i].se;
      while(!cost.empty() && curr_cost > rem){
        curr_cost -= cost.top();
        cost.pop();
      }
      Max_Cakes = max(Max_Cakes, (ll)sz(cost));
    }
    cout << Max_Cakes << "\n";
  }
  Time
  return 0;
}