#include <iostream>
#include <cstdio>
#include <vector>
#include <numeric>
#include <algorithm>
#include <utility>

using namespace std;

int n;
vector<int> w;
int half;

bool add(int sum, int idx) {
	if (sum == half) {
		return true;
	} else if (sum > half) {
		return false;
	}

	for (int i = idx + 1; i < n; i++) {
		if(add(sum + w[idx], i)) {
			return true;
		}
	}
	return false;
}

int main() {

	cin >> n;

	w.assign(n, 0);
	for (int i = 0; i < n; i++) {
		cin >> w[i];
	}
	int total = accumulate(w.begin(), w.end(), 0);

	sort(w.begin(), w.end(), greater<int>());

	bool ret = false;
	if (total % 2 == 0) {
		half = total / 2;
		ret = add(0, 0);
	}

	cout << (ret ? "possible" : "impossible") << endl;
	return 0;
}