#include<bits/stdc++.h>
 
using namespace std ;
typedef long long ll ;
 
ll n, threshold, speed[100005] ;
 
ll answer(){
 
	ll left = 0, right = threshold + 1, mid ;
 
	while(right > left + 1){
 
		mid = (left + right) / 2 ;
 
		ll y = 0, z = 0 ;
		for(ll i = 0 ; i < n ; i++){
			if(speed[i] > mid) y += (speed[i] - mid) / 3 ;
			else z += (mid - speed[i] + 1) / 2 ; // +1 addition for ceil value
		}
 
		if(y >= z) left = mid ;
		else right = mid ;
 
	}
 
	return left ;
 
}
 
void solve(){
 
	cin >> n >> threshold ;
	for(ll i = 0 ; i < n ; i++) cin >> speed[i] ;
 
	cout << answer() << '\n' ;
 
}
 
int main(){
 
	ll t ; cin >> t ;
	while(t--) solve() ;
 
	return 0 ;
}

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