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

using i64 = long long;

int main() {
    cin.tie(nullptr)->sync_with_stdio(false);

    auto solve = [&]() {
        int n;
        cin >> n;

        vector<int> w(n);
        for (int i = 0; i < n; i++) {
            cin >> w[i];
        }

        int V = accumulate(w.begin(), w.end(), 0);
        if (V % 2 == 1) {
            cout << "impossible\n";
            return;
        }

        vector<int> dp(V + 1);
        dp[0] = true;

        for (auto w : w) {
            for (int i = V; i >= w; i--) {
                dp[i] |= dp[i - w];
            }
        }

        cout << (dp[V / 2] ? "possible" : "impossible") << '\n';
    };
    
    solve();
    
    return 0;
}