#include <bits/stdc++.h>
using namespace std;

int main() {
	int n;
	cin >> n;
	int w[n];
	for (auto &i : w) {
		cin >> i;
	}
	int sum = accumulate(w, w + n, 0);
	bool dp[n + 1][sum / 2 + 1]{};
	dp[0][0] = true;
	for (int i = 0; i < n; i++) {
		for (int j = 0; j <= sum / 2; j++) {
			dp[i + 1][j] |= dp[i][j];
			if (0 <= j - w[i]) {
				dp[i + 1][j] |= dp[i][j - w[i]];
			}
		}
	}
	cout << (!(sum & 1) && dp[n][sum / 2] ? "possible" : "impossible") << endl;
	return 0;
}