#include "bits/stdc++.h"
using namespace std;

/*第二引数で第一引数を割ったときの切り上げの計算*/
long long int maxtime(long long int x, long long int y) {
	return(x + y - 1) / y;

}
/*最大公約数*/
long long int lcm(long long int number1, long long int number2) {
	long long int m = number1;
	long long int n = number2;

	if (number2 > number1) {
		m = number2;
		n = number1;
	}
	long long int s = -1;
	while (s != 0) {
		s = m % n;
		m = n;
		n = s;
	}
	return m;
}
/*最大公倍数*/
long long int gcd(long long int number1, long long int number2) {
	long long int m = number1;
	long long int n = number2;
	return m / lcm(m, n) * n;
}
int dp[120][100020] = {};
int main() {
	int N;
	cin >> N;
	dp[0][0] = 1;
	int sum = 0;
	for (int i = 1; i <= N; i++) {
		int a;
		cin >> a;
		sum = sum + a;
		for (int j = 0; j < 10020; j++) {
			if (dp[i - 1][j] == 1) {
				dp[i][j + a] = 1;
			}
		}
	}
	if (sum % 2 == 1) {
		cout << "impossible";
	}
	else {
		for (int i = 0; i <= 120; i++) {
			if (dp[i][sum / 2] == 1) {
				cout << "possible";
				return 0;
			}
		}
	}
	cout << "impossible";
}