#include <bits/stdc++.h>

using namespace std;

int main() {
    int n;
    cin >> n;

    vector<int> weight(n);
    int sum = 0;

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

    if (sum % 2 == 1) {
        cout << "impossible" << endl;
        return 0;
    }

    bool dp[101][10001];

    for (int i = 0; i < 101; ++i) {
        for (int j = 0; j < 1001; ++j) {
            dp[i][j] = false;
        }
    }

    dp[0][0] = true;
    for (int i = 0; i < n; ++i) {
        for (int j = 0; j < sum / 2 + 1; ++j) {
            if (dp[i][j]) {
                dp[i + 1][j + weight[i]] = true;
                dp[i + 1][j] = true;
            }
        }
    }

    if (dp[n][sum / 2]) {
        cout << "possible" << endl;
    } else {
        cout << "impossible" << endl;
    }
    return 0;
}