#include <bits/stdc++.h>

using namespace std;

#define REP(i, n) for(int i = 0; i < n; i++)

int main() {
    int n;
    cin >> n;
    vector<int> weight(n);
    int sum = 0;
    REP(i, n) {
        cin >> weight[i];
        sum += weight[i];
    }
    if (sum % 2 == 1) {
        cout << "impossible" << endl;
        return 0;
    }

    bool dp[101][10001];
    REP(i, 101) REP(j, 10001) dp[i][j] = false;
    dp[0][0] = true;
    REP(i, n) {
        REP(j, sum / 2 + 1) {
            if (dp[i][j] == true) {
                dp[i + 1][j + weight[i]] = true;
                dp[i + 1][j] = true;
            }
        }
    }

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