#include <iostream>
#include <bitset>

void solve() {
    int n;
    std::cin >> n;

    int wsum = 0;
    std::bitset<20000> dp;
    dp[0] = 1;

    while (n--) {
        int w;
        std::cin >> w;

        wsum += w;
        dp |= (dp << w);
    }

    std::cout << (wsum % 2 == 0 && dp[wsum / 2] ? "possible" : "impossible")
              << std::endl;
}

int main() {
    std::cin.tie(nullptr);
    std::ios::sync_with_stdio(false);

    solve();

    return 0;
}