import java.util.*;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        boolean[] isPossible = new boolean[n * 100 + 1];
        isPossible[0] = true;
        int total = 0;
        for (int i = 0; i < n; i++) {
            int x = sc.nextInt();
            total += x;
            for (int j = i * 100; j >= 0 ; j--) {
                isPossible[j + x] |= isPossible[j];
            }
        }
        if (total % 2 == 1 || !isPossible[total / 2]) { 
            System.out.println("impossible");
        } else {
            System.out.println("possible");
        }
    }
}