#include <bits/stdc++.h>

using namespace std;

#define REP(i, n)   for(int i = 0; i < (n); i++)
#define REPS(i, n)  for(int i = 1; i <= (n); i++)
#define RREP(i, n)  for(int i = (n)-1; i >= 0; i--)
#define RREPS(i, n) for(int i = (n); i > 0; i--)
#define ALL(v) v.begin(), v.end()
#define RALL(v) v.rbegin(), v.rend()
#define UNIQUE(v) v.erase(unique(v.begin(), v.end()), v.end())
#define mp make_pair
#define mt make_tuple
#define pb push_back

using ll  = long long;
using pi  = pair<int, int>;
using pl  = pair<ll, ll>;
using vi  = vector<int>;
using vl  = vector<ll>;
using vs  = vector<string>;
using vvi = vector<vi>;

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

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

int main()
{
    cin.tie(0);
    ios::sync_with_stdio(false);
    cout << fixed << setprecision(10);

    int N; cin >> N;
    int sum = 0;
    vi W(N); REP(i, N) cin >> W[i], sum += W[i];
    vector<bool> dp(10010, false);
    dp[0] = true;
    REP(i, N)
    {
        RREP(j, 10010)
        {
            if(dp[j]) dp[j+W[i]] = true;
        }
    }
    REP(i, (int)dp.size())
    {
        if(dp[i] && i == sum-i)
        {
            cout << "possible" << endl;
            return 0;
        }
    }
    cout << "impossible" << endl;
}