#include <bits/stdc++.h>
#define FOR(i,a,b) for(int i = (a); i < (b); ++i)
#define REP(i,n) FOR(i,0,n)
#define SZ(n) (int)(n).size()
#define ALL(n) (n).begin(), (n).end()
#define MOD % 1000000007
#define INF 100000000
using namespace std;
typedef long long LL;
typedef vector<int> VI;
typedef pair<int, int> PI;


int main() {
	int n;
	int w[101] = {};
	cin >> n;
	int sum = 0;
	bool bo[10101] = { false };
	REP(i, n) {
		cin >> w[i];
		sum += w[i];
	}
	bo[0] = true;
	REP(i, n) {
		for (int j = sum / 2; j >= w[i]; --j) {
			bo[j] |= bo[j - w[i]];
		}
	}
	cout << (bo[sum / 2] && sum % 2 == 0 ? "possible" : "impossible") << endl;
	return 0;
}