#include <bits/stdc++.h>

using namespace std;

#define rep(i, n) for(int i = 0; i < (int)n; ++i)
#define FOR(i, a, b) for(int i = a; i < (int)b; ++i)
#define rrep(i, n) for(int i = ((int)n - 1); i >= 0; --i)

typedef long long ll;
typedef long double ld;

const int Inf = 1e9;
const double EPS = 1e-9;
const int MOD = 1e9 + 7;
const int N = 10010;

int main() {
    cin.tie(nullptr);
    ios::sync_with_stdio(0);
    int n, sum = 0;
    cin >> n;
    vector<int> w(n), dp(N);
    rep (i, n) {
        cin >> w[i];
        sum += w[i];
    }
    if (sum % 2) {
        cout << "impossible" << endl;
        return 0;
    }
    dp[0] = 1;
    rep (i, n) {
        rrep (j, N) {
            if (!dp[j] || j + w[i] >= N) continue;
            dp[j + w[i]] = 1;
        }
    }
    if (dp[sum / 2]) cout << "possible" << endl;
    else cout << "impossible" << endl;
    
    return 0;
}