#include <iostream>

using namespace std;

bool dp[110][5010];

int main() {
	int n = 0;
	int w[110];
	int weight = 0;
	cin >> n;
	for (int i = 1; i <= n; i++) {
		cin >> w[i];
		weight += w[i];
	}
	if (weight % 2 == 1) {
		cout << "impossible\n";
		return 0;
	}
	weight /= 2;
	for (int i = 0; i <= n; i++) {
		dp[0][i] = false;
		dp[i][0] = true;
	}
	for (int i = 1; i <= n; i++) {
		for (int j = 1; j <= weight; j++) {
			if (j<w[i] ) {
				if ( dp[i - 1][j] == true) {
					dp[i][j] = true;
				}
				else {
					dp[i][j] = false;
				}
			}
			else {
				if (dp[i - 1][j - w[i]] == true || dp[i - 1][j] == true) {
					dp[i][j] = true;
				}
				else {
					dp[i][j] = false;
				}
			}
		}
	}

	if (dp[n][weight]) {
		cout << "possible\n";
	}else{
		cout << "impossible\n";
	}
	return 0;
}