#include <iostream>
#include <algorithm>

using namespace std;

int main() {
    const int W_SUM_MAX = 1000000;
    int n;
    int w[101];
    bool dp[W_SUM_MAX];
    int w_sum_half = 0;
    fill(dp, dp + W_SUM_MAX, 0);
    cin >> n;
    for (int i = 0; i < n; i++) {
        cin >> w[i];
        w_sum_half += w[i];
    }
    if (w_sum_half % 2 == 1) {
        cout << "impossible" << endl;
        return 0;
    }
    w_sum_half = w_sum_half / 2;
    for (int i = 0; i < n; i++) {
        for (int j = w_sum_half; j >= w[i]; j--) {
            dp[j] = dp[j] || dp[j - w[i]] || (j - w[i] == 0);
        }
    }
    if (dp[w_sum_half]) {
        cout << "possible" << endl;
    } else {
        cout << "impossible" << endl;
    }
    return 0;
}