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

int main() {
    const int MAX = 100 * 100;
    int n; cin >> n;
    vector<int> w(n);
    for (int &wi: w) cin >> wi;
    vector<int> dp(MAX + 1, 0);
        dp[0] = 1;
    for (int wi: w) {
        for (int i = MAX - wi; i >= 0; i--) dp[i + wi] |= dp[i];
    }
    int sum = accumulate(w.begin(), w.end(), 0);
    if (sum % 2 == 0) {
        cout << (dp[sum / 2] ? "possible" : "impossible") << endl;
    } else {
        cout << "impossible" << endl;
    }
    return 0;
}