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

#define times(n, i)      uptil(0, n, i)
#define rtimes(n, i)     downto((n) - 1, 0, i)
#define upto(f, t, i)    for(int i##_to_ = (t), i = (f); i <= i##_to_; i++)
#define uptil(f, t, i)   for(int i##_to_ = (t), i = (f); i <  i##_to_; i++)
#define downto(f, t, i)  for(int i##_to_ = (t), i = (f); i >= i##_to_; i--)
#define downtil(f, t, i) for(int i##_to_ = (t), i = (f); i >  i##_to_; i--)
typedef long double LD;
#define long long long

#if defined(EBUG) && !defined(ONLINE_JUDGE)
#define debug true
#define _GLIBCXX_DEBUG
#define _LIBCPP_DEBUG 2
#define _LIBCPP_DEBUG2 2
#define ln << endl
#else
#define debug false
#define ln << '\n'
#endif
#define tb << '\t'
#define sp << ' '



signed main() { // long: 64bit
    if(!debug) {
        cin.tie(0);
        ios::sync_with_stdio(0);
    }

    int N; scanf("%d", &N);

    vector<int> pyon(10001, false);
    pyon[0] = true;

    int sum = 0;
    times(N, i) {
        int W; scanf("%d", &W);
        sum += W;
        upto(0, 10000, i) {
            for(int j : {i + W}) {
                if(0 <= j && j <= 10000) {
                    pyon[j] = pyon[j] || pyon[i];
                }
            }
        }
    }

    cout << (sum % 2 == 0 && pyon[sum / 2] ? "possible" : "impossible") ln;

    return 0;
}