#include<iostream>
using namespace std;

int n;
int w[100];
int sum = 0;
bool judge[10001] = { false };

int main() {
	cin >> n;
	judge[0] = true;
	for (int i = 0; i < n; i++) {
		cin >> w[i];
		sum += w[i];
		for (int j = 10000; j >= w[i]; j--) {
			if (judge[j - w[i]]) judge[j] = true;
		}
	}
	if (sum % 2 == 0 && judge[sum / 2]) {
		cout << "possible" << endl;
	}
	else {
		cout << "impossible" << endl;
	}
	return 0;
}