#include <iostream>

using namespace std;

bool dp[105][10005];

int main() {
	int n, w[105],sum=0;
	cin >> n;
	for (int i = 0; i < n; i++) {
		cin >> w[i];
		sum += w[i];
	}
	if (sum % 2 == 1) {
		cout << "impossible";
		return 0;
	}
	for (int i = 0; i < n; i++) {
		dp[i][0] = true;
	}
	for (int i = 0; i < sum / 2; i++) {
		if (i == w[0])dp[0][i] = true;
		else dp[0][i] = false;
	}
	for (int i = 1; i <=sum/2; i++) {
		for (int j = 1; j < n; j++) {
			dp[j][i] = false;
			if (i - w[j] < 0) continue;
			for (int k = 0; k < j; k++) {
				if (dp[k][i - w[j]]) {
					dp[j][i] = true;
					break;
				}
			}
		}
	}
	for (int i = 0; i < n; i++) {
		if (dp[i][sum / 2]) {
			cout << "possible";
			return 0;
		}
	}
	cout << "impossible";
	return 0;
}