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

int n;
ll sum;
int w[10001];

bool f(int index, int weight) {

    if (weight == sum / 2)
        return true;
    if (weight > sum/2)
        return false;
    if (index == n)
        return false;

    return f(index+1, weight) || f(index+1, weight + w[index]);
}

int main() {
    ios::sync_with_stdio(false);
    cin >> n;

    for (int i = 0; i < n; i++) {
        cin >> w[i];
        sum += w[i];
    }
    if (sum & 1) {
        cout << "impossible\n";
        return 0;
    }

    if (f(0,0)) {
        cout << "possible\n";
    } else {
        cout << "impossible\n";
    }
    








    return 0;
}