#include "bits/stdc++.h"
using namespace std;
typedef long long ll;
#define INF (1<<30)
#define INFLL (1ll<<60)
typedef pair<double, int> P;
typedef pair<int, P> E;
#define MOD (1000000007ll)
#define l_ength size
#define EPS (1e-10)

void add_mod(ll &a, ll b){
	a += b;
	a %= MOD;
}

void mul_mod(ll &a, ll b){
	a *= b;
	a %= MOD;
}

int main(void){
	int n,i,j,w[123],s=0;
	bool p[12345];
	cin >> n;
	fill(p,p+12345,true);
	p[0] = false;
	for(i=0; i<n; ++i){
		cin >> w[i];
		s += w[i];
	}
	for(i=0; i<n; ++i){
		for(j=w[i]; j<=10000; ++j){
			if(!p[j-w[i]]){
				p[j] = false;
			}
		}
	}
	cout << ((s%2 || p[s/2])?"im":"") << "possible" << endl;
	return 0;
}