#include <bits/stdc++.h> 

#define int long long

#define REP(i, b) for(int i = 0; i < (b); i++)
#define REPS(i, b) for(int i = 1; i <= (b); i++)
#define ALL(v) (v).begin(), (v).end()

using namespace std;

using pi = pair<int, int>;
using vi = vector<int>;
using vs = vector<string>;
using vb = vector<bool>;
using vpi = vector<pi>;
using vvi = vector<vi>;
using vvb = vector<vb>;

const int INF = 1e10;
const int MOD = 1e9+7;

template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return true; } return false; }
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return true; } return false; }

signed main()
{
    cin.tie(nullptr);
    ios_base::sync_with_stdio(false);
    cout << fixed << setprecision(10);

    int N; cin >> N;
    vi W(N); REP(i, N) cin >> W[i];
    vvb dp(N+1, vb(10010, false));
    dp[0][0] = true;
    REP(i, N)
    {
        REP(j, 10010)
        {
            if(dp[i][j]) 
            {
                dp[i+1][j] = true;
                dp[i+1][j+W[i]] = true;
            }
        }
    }

    int w = 0; REP(i, N) w += W[i];
    if(w % 2 == 0 && dp[N][w/2]) cout << "possible" << endl;
    else cout << "impossible" << endl;
}