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


void solve(){
	int n, k;
	cin >> n >> k;
	vector<int> arr(n);
	for(int i = 0; i < n; i++)
		cin >> arr[i];
	sort(arr.begin(), arr.end());
	int maxSum = 0;
	int l = 0, r = n-1, pivot;
	for(int i = 0; i < n; i++){
		l = 0;
		r = n-1;
		while(l < r){
			pivot = (l+r)/2;
			long long power = pow(arr[i], arr[pivot]);

			if(power == k && arr[i] != arr[pivot]){
				maxSum = max(maxSum, arr[pivot]+arr[i]);
				break;
			}
			if(power <= k)
				l = r+1;
			if(power > k)
				r = l-1;
		}
	}
	cout << maxSum << endl;


}

int main(){
	int t; cin >> t;
	while(t--)
		solve();
	return 0;
}