#include <iostream>
#include <vector>
using namespace std;

int main() {
    int N;
    cin >> N;
    vector<int> W(N);
    int S = 0;
    for (int i = 0; i < N; ++i) {
        cin >> W[i];
        S += W[i];
    }

    vector<vector<bool>> dp(N + 1, vector<bool>(S + 1, false));
    dp[0][0] = true;
    for (int i = 1; i <= N; ++i) {
        for (int w = 0; w <= S; ++w) {
            dp[i][w] = dp[i - 1][w];
            if (w - W[i - 1] >= 0) {
                dp[i][w] = dp[i][w] || dp[i - 1][w - W[i - 1]];
            }
        }
    }

    if (dp[N][S / 2] && !(S % 2)) {
        cout << "possible" << endl;
    } else {
        cout << "impossible" << endl;
    }
}