#include <bits/stdc++.h>

using namespace std;
using ll = long long;
using PII = std::pair<int, int>;
using PLL = std::pair<ll, ll>;

#define rep(i, n) for (int i = 0; i < (int)(n); i++)
#define rep2(i, s, n) for (int i = (s); i < (int)(n); i++)


int main()
{

#ifdef DEBUG
    cout << "DEBUG MODE" << endl;
    ifstream in("input.txt"); //for debug
    cin.rdbuf(in.rdbuf());    //for debug
#endif

    int n, x, s, maxorder;
    cin >> n;
    string ans = "impossible";
    int weight[n];
    rep(i, n)
        cin >> weight[i];
    s = accumulate(weight, weight + n, 0);
    vector<bool> dp;
    dp.resize(s + 1);
    fill(dp.begin(), dp.end(), false);
    dp[0] = true;

    rep(i, n)
    {
        for (int j = s + 1; j > 0; j--)
        {
            if (j - weight[i] >= 0)
                dp[j] = dp[j] | dp[j - weight[i]];
        }

    }

    if (!(s % 2) && dp[s / 2])
        ans = "possible";
    
    cout << ans << endl;


    return 0;
}