#include <iostream>
#include <vector>
#include <string>
#include <numeric>
#include <algorithm>
using namespace std;
typedef pair<int, int> pii;
int N;
int W[101], sum[101];
vector<pii> dp[101];
string ans = "impossible";
int main(void) {
	cin >> N;
	dp[0].push_back(pii(0, 0));
	for (int n = 1; n <= N; ++n) cin >> W[n];
	sum[1] = accumulate(W + 1, W + N + 1, 0);
	for (int n = 2; n <= N; ++n) {
		sum[n] = sum[n - 1] - W[n - 1];
	}
	for (int n = 1; n <= N; ++n) {
		for (size_t idx = 0U; idx < dp[n - 1].size(); ++idx) {
			pii pre = dp[n - 1][idx];
			if (abs(pre.first + W[n] - pre.second) <= sum[n]) dp[n].push_back(pii(pre.first + W[n], pre.second));
			if (abs(pre.first - (pre.second + W[n])) <= sum[n]) dp[n].push_back(pii(pre.first, pre.second + W[n]));
		}
	}
	for (size_t idx = 0U; idx < dp[N].size(); ++idx) {
		if (dp[N][idx].first == dp[N][idx].second) ans = "possible";
	}
	cout << ans << endl;
	return 0;
}