#include <iostream>
#include <vector>
#include <algorithm>
#include <functional>

using namespace std;

int main() {
    int n;
    cin >> n;

    vector<int> w(n);
    for (int i=0;i<n;i++) cin >> w[i];

    sort(w.begin(), w.end(), greater<int>());
    int t = 0;
    int th =0;
    for (int a : w ) t += a;

   if (t%2!=0) {
        cout << "impossible" << endl;
        return 0;
    }

    th = t/2;

    vector<vector<int>> m(n, vector<int>(th+1, 0));

    int i, j;

    for (j=0;j<=th;j++) {
        if (j<w[0]) continue;
        else m[0][j] = w[0];
    }

    for (i=1;i<n;i++) {
        for (j=0;j<=th;j++) {
            
            if (j<m[i-1][j] + w[i]) {m[i][j] = m[i-1][j];}
            else {m[i][j] = m[i-1][j] + w[i];}

            if (m[i][j]==th) {cout << "possible" << endl; return 0;}
        }
    }

    cout << "impossible" << endl;
    return 0;
}