import java.util.*;
import java.math.*;
import java.io.*;
 
public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		int[] w = new int[n];
		int sum = 0;
		for(int i = 0; i < n; i++) {
			w[i] = sc.nextInt();
			sum += w[i];
		}
		boolean[][] dp = new boolean[n+1][sum+1];
		dp[0][0] = true;
		for(int i = 0; i < n; i++) {
			for(int j = 0; j <= sum; j++) {
				if(!dp[i][j]) continue;
				dp[i+1][j] |= dp[i][j];
				dp[i+1][j + w[i]] = true; 
			}
		}
		if(sum % 2 == 0 && dp[n][sum / 2]) {
			System.out.println("possible");
		}
		else {
			System.out.println("impossible");
		}
	}
}