#include <iostream>
#include <vector>

using namespace std;

int main(int argc, char const* argv[]) {
    int N;
    cin >> N;
    vector<int> W(N);
    int sum = 0;
    for (int i = 0; i < N; i++) {
        cin >> W[i];
        sum += W[i];
    }

    int MAX = sum / 2 + 10;
    bool dp[MAX];
    dp[0] = true; for(int i = 1; i < MAX; i++) dp[i] = false;

    for (int i = 0; i < N; i++) {
        for (int w = MAX; w >= W[i]; w--) {
            dp[w] |= dp[w-W[i]];
        }
    }

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