#include <bits/stdc++.h>
using namespace std;
#define FOR(i, n) for(int i = 0; i < (n); i++)
#define MEM(a, x) memset(a, x, sizeof(a))
#define ALL(a) a.begin(), a.end()
#define UNIQUE(a) a.erase(unique(ALL(a)), a.end())
typedef long long ll;

int n;
bool dp[10005];

int main(int argc, char const *argv[]) {
	ios_base::sync_with_stdio(false);
	cin >> n;
	int sum = 0;
	dp[0] = true;
	FOR(i, n) {
		int w;
		cin >> w;
		FOR(j, 10005) {
			if (j+w < 10005) dp[j+w] = dp[j+w] || dp[j];
		}
		sum += w;
	}
	cout << (sum & 1 || !dp[sum/2] ? "impossible" : "possible") << endl;
	return 0;
}