#include<iostream>
using namespace std;


int main(void)
{
	int n, sum = 0;
	int m[100];
	int dp[10010];
		dp[0] = 1;

	cin >> n;
	for (int i = 0; i < n; i++) {
		cin >> m[i];
		sum += m[i];
		for (int j = sum; j >= 0;j--){
			if (dp[j] == 1) {
				dp[j + m[i]] = 1;//m[i]+jの重さはつくれる
			}

		}
	}

	if (sum % 2 == 0 && (dp[sum/2] == 1)) {
		cout << "possible" << endl;
	}
	else {
		cout << "impossible" << endl;
	}


	return 0;
}