#include <iostream>
#include <vector>

bool solve(int N, std::vector<int> W) {
    int S = 0;
    for (int i = 0; i < N; i++) {
        S += W[i];
    }
    if (S % 2 == 1) {
        return false;
    }
    int M = S / 2;
    std::vector<bool> dp(M + 1, false);
    dp.at(0) = true;
    for (const auto &w: W) {
        for (int x = M - w; x >= 0; x--) {
            if (dp.at(x)) {
                dp.at(x + w) = true;
            }
        }
    }
    return dp.at(M);
}

int main() {
    int N;
    std::cin >> N;

    std::vector<int> W(N);
    for (int i = 0; i < N; i++) { std::cin >> W[i]; }

    std::string ans = solve(N, W) ? "possible" : "impossible";
    std::cout << ans << std::endl;
}