#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define rep(i, n) for(ll i = 0, i##_len = (n); i < i##_len; i++)
#define reps(i, s, n) for(ll i = (s), i##_len = (n); i < i##_len; i++)
#define rrep(i, n) for(ll i = (n) - 1; i >= 0; i--)
#define rreps(i, e, n) for(ll i = (n) - 1; i >= (e); i--)
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
#define sz(x) ((ll)(x).size())
#define len(x) ((ll)(x).length())
#define endl "\n"

int main() {
    cin.tie(0);
    ios::sync_with_stdio(false);
    // ifstream in("input.txt");
    // cin.rdbuf(in.rdbuf());
    ll n;
    cin >> n;
    vector<ll> w(n);
    rep(i, n) cin >> w[i];
    vector<bool> dp(10001, false);
    dp[0] = true;
    rep(i, n) {
        rrep(j, sz(dp) - w[i]) {
            if (!dp[j]) continue;
            dp[j + w[i]] = true;
        }
    }
    ll sumw = accumulate(all(w), 0LL);
    if ((sumw % 2 == 0) && (dp[sumw / 2])) {
        cout << "possible" << endl;
    }
    else {
        cout << "impossible" << endl;
    }
    return 0;
}