import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import static java.lang.System.in;

public class Main {
    public static void main(String[] args) throws IOException {
        BufferedReader reader = new BufferedReader(new InputStreamReader(in));
        int N = Integer.parseInt(reader.readLine());
        String[] inputs = reader.readLine().split(" ");
        int[] weights = new int[N];
        int sumOfWeights = 0;

        for (int i = 0; i < N; i++) {
            int weight = Integer.parseInt(inputs[i]);
            weights[i] = weight;
            sumOfWeights += weight;
        }

        if (sumOfWeights % 2 != 0) {
            System.out.println("impossible");
        } else {

            int requiredWeight = sumOfWeights / 2;
            boolean[][] dp = new boolean[101][10001];
            dp[0][0] = true;

            for (int i = 0; i < N; i++) {
                for (int j = 0; j <= 10000; j++) {
                    if (dp[i][j]) {
                        dp[i + 1][j + weights[i]] = true;
                        dp[i + 1][j] = true;
                    }
                }
            }
            if (dp[N][requiredWeight]) {
                System.out.println("possible");
            } else {
                System.out.println("impossible");
            }
        }
    }
}