import java.util.*;
import java.util.stream.*;

public class Main {
    private void solve() {
        Scanner sc = new Scanner(System.in);
        int n = Integer.parseInt(sc.nextLine());
        int[] ws = Stream.of(sc.nextLine().split(" "))
                              .mapToInt(Integer::parseInt)
                              .toArray();
        int sum = Arrays.stream(ws).sum();
        boolean[] ok = new boolean[sum+1];
        ok[0] = true;
        for(int w : ws) {
            for(int i=sum; i>=0; i--) {
                if(ok[i]) { ok[i+w] = true; }
            }
        }
        System.out.println(ok[sum/2] && sum%2==0 ? "possible" : "impossible");
    }

    public static void main(String[] args) {
        new Main().solve();
    }
}