#include <bits/stdc++.h>
using namespace std;

// 基本テンプレート
struct cww{cww(){ios::sync_with_stdio(false);cin.tie(0);cout << fixed << setprecision(0);}}star;
#define P(x) cout << (x) << endl
#define p(x) cout << (x)
#define ALL(c) (c).begin(), (c).end()
#define RALL(c) (c).rbegin(), (c).rend()
#define MAT(type, c, m, n) vector<vector<type>> c(m, vector<type>(n));for(auto& r:c)for(auto& i:r)cin>>i;
#define VV(type, c, m, n, i) vector<vector<type>> c(m, vector<type>(n, i));
#define REP(i,a,n) for(int i=(a), i##_len=(n); i<i##_len; ++i)
#define RREP(i,a,n) for(int i=(a); i>n; --i)
#define perm(c) sort(ALL(c));for(bool c##p=1;c##p;c##p=next_permutation(ALL(c)))
#define PB push_back
#define EM emplace
#define EB emplace_back
#define BI back_inserter
#define MP make_pair
#define cauto const auto&
#define UNIQUE(v) v.erase( unique(ALL(v)), v.end() );
#define len(x) ((int)(x).size())
#define GET_ARRAY_SIZE(a)   (sizeof(a)/sizeof(a[0]))


// 型
typedef long long ll;
typedef unsigned long long ull;
typedef pair<int, int> pii;
typedef pair<string, string> pss;
typedef pair<string, int> psi;
typedef pair<int, string> pis;
typedef vector<int> vi;
typedef vector<double> vd;
typedef vector<long> vl;
typedef vector<long long> vll;
typedef vector<string> vs;

// 定数
#define PI acos(-1.0)
constexpr int EPS = (1e-9);
constexpr int INF = 100000000;

#define MAX 10000


void knapsack() {
	int n; cin >> n;
	int sum = 0;
	vi w(n); for (auto &i : w) {cin >> i; sum += i; }
	if (sum % 2 != 0) {P("impossible"); return;}
	sum /= 2;

	VV(int, dp, n + 1, sum + 1, 0);

	RREP(i, n - 1, -1) {
		REP(j, 0, sum + 1) {
			if (j < w[i]){
				dp[i][j] = dp[i + 1][j];
			} else {
				dp[i][j] = max(dp[i + 1][j], dp[i + 1][j - w[i]] + w[i]);
			}
		}
	}

	P(dp[0][sum] == sum ? "possible" : "impossible");

}



int main() {
//	cout << setprecision(0) << fixed;

    knapsack();
    return 0;
}