#include <bits/stdc++.h>
#define rep(i, n) for(long long i = 0; i < n; i++)
#define ALL(v) (v).begin(), (v).end()
using namespace std;

using lint = long long;

int main() {
    int n;
    cin >> n;
    vector<int> w(n);
    rep(i, n) {
        cin >> w[i];
    }
    int s = accumulate(ALL(w), 0);
    vector<vector<int>> dp(n + 1, vector<int>(s + 1, false));
    dp[0][0] = 1;
    for (int i = 1; i <= n; i++) {
        for (int j = 0; j <= s; j++) {
            dp[i][j] |= dp[i - 1][j];
            if (j - w[i - 1] >= 0) {
                dp[i][j] |= dp[i - 1][j - w[i - 1]];
            }
        }
    }
    cout << ((s % 2 == 0 && dp[n][s / 2] == 1) ? "possible" : "impossible") << endl;
}