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

using namespace std;


int main()
{
	int N;
	cin >> N;
	int a;
	bool dp[10001] = {}, dp2[10001] = {};
	int sum = 0;
	for (size_t i = 0; i < N; i++)
	{
		cin >> a;
		sum += a;
		for (size_t j = 0; j < 10001; j++)
		{
			if (dp[j])
			{
				dp2[j + a] = 1;
			}
		}
		dp[a] = 1;
		for (size_t i = 0; i < 10001; i++)
		{
			dp[i] |= dp2[i];
		}
	}
	if (!(sum%2)&&dp[sum / 2])
	{
		cout << "possible" << endl;
	} else
	{
		cout << "impossible" << endl;
	}
	return 0;
}