#include <iostream>
#include <string>
#include <numeric>
using namespace std;

bool isDevideInHalf(int* weights, int n, int index, int total_weight) {
	if (total_weight == 0) return true;
	if (index >= n) return false;

	if (weights[index] <= total_weight) {
		if (isDevideInHalf(weights, n, index + 1, total_weight - weights[index]))
			return true;
		return isDevideInHalf(weights, n, index + 1, total_weight);
	}

	return isDevideInHalf(weights, n, index + 1, total_weight);
}

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

	int weights[100];
	for (int i = 0; i < n; i++) {
		cin >> weights[i];
	}

	bool is_possible = false;
	int sum_weight = accumulate(weights, weights + n, 0);
	if (sum_weight % 2 == 0) {
		is_possible = isDevideInHalf(weights, n, 0, sum_weight / 2);
	}
	
	string answer = is_possible ? "possible" : "impossible";
	cout << answer << endl;

	return 0;
}