#include <bits/stdc++.h>
using namespace std;
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
#define srep(i, s, n) for (int i=(s); i < (int)(n); i++)
#define all(v) v.begin(), v.end()
#define fore(i,x) for(auto i:x)
#define pb push_back

using vi=vector<int>;
using vvi=vector<vi>;
using vb=vector<bool>;
using vvb=vector<vb>;
using vs=vector<string>;
using vll=vector<long long>;
using vvll=vector<vll>;
using vc=vector<char>;
using vvc=vector<vc>;
using ll=long long;

void Yes(bool ok){ cout << (ok ? "Yes" : "No") << "\n";}

int main(){
    int N; cin >> N;
    vi W(N);
    rep(i,N) cin >> W.at(i);
    int S=0;
    vvb dp(N+1,vb(10001));
    dp.at(0).at(0)=true;
    rep(i,N) S+=W.at(i);
    bool ans=false;
    if(S%2==0){
        rep(i,N){
            rep(j,10001){
                if(dp.at(i).at(j)){
                    dp.at(i+1).at(j)=true;
                    dp.at(i+1).at(j+W.at(i))=true;
                }
            }
        }
        rep(i,N+1){
            if(dp.at(i).at(S/2)) ans=true;
        }
    }
    if(ans) cout << "possible" << "\n";
    else cout << "impossible" << "\n";
}