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

int main() {
    ios::sync_with_stdio(false);
    int n; cin >> n;
    int a[n], b[n], c[n];
    for (int i = 0; i < n; i++)
        cin >> a[i];

    sort(a, a+n);

    c[n-1] = a[n-1];
    b[0] = a[0];
    for (int i = 1; i < n; i++) {
        b[i] = b[i-1] + a[i];

    }
    for (int i = n-2; i >=0; i--) {
        c[i] = c[i+1] + a[i];
    }
    for (int i = 0; i < n; i++) {
        for (int j = n-1; j > i ; j--) {
            if (b[i] == c[j]) {
                    cout << "possible\n";
                    return 0;
            }
        }
    }
    cout << "impossible\n";

    return 0;
}