#include"bits/stdc++.h"
using namespace std;
using ll = long long;
using ld = long double;
#define rep(i,m,n) for(ll i=(ll)m;i<(ll)n;i++)
#define Endl endl
#define pr(i,j) make_pair(i,j) 
const ll mod = 998244353;
const ll inf = 5e18;
const ld pi = 3.14159265358979;
int main() {
	ll n;
	cin >> n;
	vector<ll>w(n);
	ll sum = 0;
	rep(i, 0, n) {
		cin >> w[i];
		sum += w[i];
	}
	set<ll>st;
	st.insert(0);
	rep(i, 0, n) {
		set<ll>copy = st;
		for (auto& j:st) {
			copy.insert(j + w[i]);
		}
		st = copy;
	}
	for (auto& j : st) {
		if (j * 2 == sum) {
			cout << "possible" << endl;
			return 0;
		}
	}
	cout << "impossible" << endl;
}