#include <iostream>
#include <cstdio>
#include <vector>
#include <numeric>
#include <algorithm>
#include <utility>

using namespace std;

int main() {
	int n;
	vector<int> w;
	int half;

	cin >> n;

	w.assign(n + 1, 0);
	for (int i = 1; i <= n; i++) {
		cin >> w[i];
	}
	int total = accumulate(w.begin(), w.end(), 0);
	bool ret = false;
	if (total % 2 == 0) {
		half = total / 2;
		// printf("total %d: half %d\n", total, half);
		vector< vector<bool> > dp;
		dp.assign(n + 1, vector<bool>(total + 1, false));
		dp[0][0] = true;

		for (int i = 0; i < n; i++) {
			for (int j = 0; j < total; j++) {
				if (dp[i][j]) {
					dp[i+1][j] = true;
					dp[i+1][j + w[i]] = true;
				}
			}
		}
		for (int i = 0; i <= n; i++) {
			if (dp[i][half]) {
				ret = true;
				break;
			}
		}
	}
	cout << (ret ? "possible" : "impossible") << endl;
	return 0;
}