# include <iostream>
# include <algorithm>
# include <vector>
# include <string>
# include <set>
# include <map>
# include <cmath>
# include <iomanip>
# include <functional>
# include <utility>
# include <stack>
# include <queue>
# include <list>
# include <bitset>
# include <complex>
# include <numeric>
# include <tuple>
using namespace std;
using LL = long long;
using ULL = unsigned long long;
constexpr int INF = 2000000000;
constexpr int HINF = INF / 2;
constexpr double DINF = 100000000000000000.0;
constexpr long long LINF = 9223372036854775807;
constexpr long long HLINF = 4500000000000000000;
const double PI = acos(-1);
int dx[4] = { 0,1,0,-1 }, dy[4] = { 1,0,-1,0 };
#define ALL(x)    (x).begin(),(x).end()
#define UNIQ(c)   (c).erase(unique(ALL((c))), end((c)))
#define mp        make_pair
#define eb        emplace_back
typedef pair<LL, double> P;
typedef pair<P, P> PP;

int n, W[10101];
bool dp[10101];
int main() {
	cin >> n;
	int sum = 0;
	for (int i = 0; i < n; i++) {
		cin >> W[i];
		sum += W[i];
	}
	dp[0] = true;
	for (int i = 0; i < n; i++) {
		for (int j = 10101 - 1 - W[i]; j >= 0; j--) {
			dp[j + W[i]] |= dp[j];
		}
	}
	if (sum % 2 == 1 || !dp[sum / 2])cout << "impossible" << endl;
	else cout << "possible" << endl;

}