#include<bits/stdc++.h>
using namespace std;
int n, x, a[25], ok;
vector<string> ans;
vector<int> v;
void Try(int i, int sum) {
	if(sum>x) return;
	if(sum==x) {
		string s="{";
		for(int i=0; i<v.size()-1; i++) s+=to_string(v[i])+" ";
		s+=to_string(v.back())+"}";
		ans.push_back(s);  
		ok=1;
	}
	for(int j=i; j<n; j++) {
		v.push_back(a[j]);
		Try(j,sum+a[j]);
		v.pop_back();
	}
}
main() {
	int t;
	cin >> t;
	while(t--) {
		cin >> n >> x;
		for(int i=0; i<n; i++) cin >> a[i];
		ok=0;
		Try(0,0);
		if(!ok) cout << "-1";
		else {
			cout << ans.size() << " ";
			for(int i=0; i<ans.size(); i++) cout << ans[i] <<" ";
		}
		cout << endl;
	}
}

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Mgo0ICA4CgoyICA0ICA2ICA4CgoyIDkKCjEwIDEx

2
4  8

2  4  6  8

2 9

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