#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using P = pair<int, int>;

bool dp[11111];

int main() {
    int n;
    cin >> n;
    int w[n], sum = 0;
    for (int i = 0; i < n; i++) {
        cin >> w[i];
        sum += w[i];
    }
    dp[0] = true;
    for (int i = 0; i < n; i++) {
        for (int j = w[i]; j < 11111; j++) {
            dp[j] |= dp[j - w[i]];
        }
    }
    if (sum % 2 == 0 && dp[sum / 2]) cout << "possible" << endl;
    else cout << "impossible" << endl;
}