#include <iostream>
#include <cmath>
#include <string>
#include <vector>
#include <map>
#include <set>
#include <list>
#include <deque>
#include <algorithm>
#include <iomanip>
#include <functional>
#include <numeric>
#include <sstream>

#define REP(i, n) for(int i = 0;i < (n); i++)
#define REP2(i, x, n) for(int i = (x); i < (n); i++)
#define RREP(i, n) for (int i = (n) - 1;i >= 0; i--)

#define ALL(a) (a).begin(),(a).end()
#define SORT(c) sort((c).begin(),(c).end())
#define DESCSORT(c) sort(c.begin(), c.end(), greater<int>())

#define LL long long int
#define LD long double

#define PI 3.14159265358979

using namespace std;

//================================================
bool func() {
	int N;
	cin >> N;
	vector<int>vec(N);

	REP(i, N) cin >> vec[i];
	int sum = accumulate(vec.begin(), vec.end(), 0);
	if (sum % 2) return false;

	vector<int>dp(10001);
	dp[0] = 1;
	REP(i, N) {
		RREP(j, 10001) {
			if (dp[j]) {
				dp[j + vec[i]] = 1;
			}
		}
	}

	if (dp[sum / 2]) return true;
	else return false;
}


int main() {
	ios::sync_with_stdio(false);
	cin.tie(0);

	if (func()) cout << "possible" << "\n";
	else cout << "impossible" << "\n";
	return 0;
}