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


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

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

	vector<int> dp(10001);
	dp[0] = 1;
	for (int i = 0; i < n; i++) {
		for (int j = dp.size() - 1; j >= 0; j--) {
			if (dp[j] == 1) {
				dp[j + weights[i]] = 1;
			}
		}
	}
	
	string answer = (sum % 2 == 0 && dp[sum / 2]) ? "possible" : "impossible";
	cout << answer << endl;

	return 0;
}