// @EXPECTED_RESULTS@: RUN_TIME_ERROR, TIME_LIMIT_EXCEEDED
#include <bits/stdc++.h>
using namespace std;

const int N = 333333;
int dp[N], go[N][2];

int main() {
	int n, m;
	cin >> n >> m;

	vector<int> a(n);
	for (int &x: a) cin >> x;
	sort(begin(a), end(a));
	a.erase(unique(begin(a), end(a)), end(a));
	n = size(a);

	if (find(begin(a), end(a), m) != end(a)) {
		cout << "possible" << '\n' << 1 << '\n' << m << '\n' << 1 << '\n' << m << '\n';
		return 0;
	}

	dp[0] = 1;
	for (int i = 1; i <= m; i++) {
		for (int x: a) {
			if (x > i) break;
			if (!dp[i-x]) continue;
			go[i][dp[i]++] = x;
			if (dp[i] == 2) break;
		}
	}

	cout << (dp[m] == 2 ? "possible" : "impossible") << '\n';
	if (dp[m] < 2) return 0;

	int j = m, k = m;
	vector<int> u, v;
	while (j+k > 0) {
		if (j < k) swap(j, k), swap(u, v);
		int x = go[j][0];
		if (j-x == k && k != 0) x = go[j][1];
		u.push_back(x), j -= x;
	}
	cout << size(u) << '\n';
	for (int x: u) cout << x << ' ';
	cout << '\n';
	cout << size(v) << '\n';
	for (int x: v) cout << x << ' ';
	cout << '\n';
}