#include<cstdio>
#include <iostream>
#include<algorithm>
#include<string>
#include<queue>
#include<vector>
#include<functional>
#include<cmath>
#include<map>
#include<stack>
#include<set>
using namespace std;
typedef long long ll;
//typedef pair<int, int> P;


int main()
{
	int w[10101] = { 1 };
	int sum=0;
	int N;  cin >> N;


	for (int i = 0; i < N; i++) {
		int t;
		cin >> t;
		sum += t;
		for (int j = 10000; j--; w[j + t] += w[j]);
	}

	cout << (sum % 2 == 1 || !w[sum / 2] ? "impossible" : "possible") << endl;
	return	0;
}