#include <bits/stdc++.h>
using namespace std;
using ll = long long;
constexpr ll inf = (1LL << 62);
template <typename T>
bool chmax(T& a, const T& b)
{
    if (a < b) {
        a = b;
        return true;
    }
    return false;
}
template <typename T>
bool chmin(T& a, const T& b)
{
    if (a > b) {
        a = b;
        return true;
    }
    return false;
}
ll dp[105][10010];
int main()
{
    memset(dp, 0, sizeof(dp));
    ll n;
    cin >> n;
    vector<ll> w(n);
    ll cnt = 0;
    for (ll i = 0; i < n; ++i) {
        cin >> w[i];
        cnt += w[i];
    }
    if (cnt % 2 != 0) {
        cout << "impossible" << endl;
    } else {
        dp[0][0] = 1;
        for (ll i = 0; i < n; ++i) {
            for (ll j = 0; j <= cnt; ++j) {
                if (j >= w[i]) {
                    dp[i + 1][j] = dp[i][j - w[i]] | dp[i][j];
                } else {
                    dp[i + 1][j] = dp[i][j];
                }
            }
        }
        if (dp[n][cnt / 2] == 1) {
            cout << "possible" << endl;
        } else {
            cout << "impossible" << endl;
        }
    }
}