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

void solve() {
        int N;
        cin >> N;
        vector<int> W(N);
        for (auto &x : W) cin >> x;
        int tot = accumulate(W.begin(), W.end(), 0);
        if (tot & 1) {
                cout << "impossible\n";
        } else {
                int target = tot / 2;
                vector<bool> dp(target + 1, false);
                dp[0] = true;
                for (auto &x : W) {
                        for (int tr = target; tr >= x; tr--) {
                                if (dp[tr - x]) dp[x] = true;
                        }
                }
                cout << (dp[target] ? "possible\n" : "impossible\n");
        }
}

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

        int t = 1;
        // cin >> t;
        while (t--) solve();

        return 0;
}