typedef long long ll;
typedef long double ld;

#include <bits/stdc++.h>
using namespace std;
// #define int long long

#include <ext/pb_ds/assoc_container.hpp>
using namespace __gnu_pbds;
template<typename T>
using ordered_set = tree<T, null_type, std::less<T>, rb_tree_tag, tree_order_statistics_node_update>;
// std::cout << *s.find_by_order(1) << std::endl; // 2

signed main(){
    // これがないと落ちることがある
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    ll n;
    cin >> n;
    vector<ll> w(n);
    ll sum = 0;
    for (ll i = 0; i < n; i++){
        cin >> w[i];
        sum += w[i];
    }
    if(sum%2==1){
        cout << "impossible" << endl;
        return 0;
    }
    vector<vector<bool>> dp(n+1, vector<bool>(sum/2+1));
    dp[0][0] = true;
    for (ll i = 0; i < n; i++){
        for (ll j = 0; j <= sum/2; j++){
            dp[i+1][j] = dp[i][j] || dp[i][j-w[i]];
        }
    }
    if(dp[n][sum/2]){
        cout << "possible" << endl;
    }else{
        cout << "impossible" << endl;
    }


}