#include <iostream>
#include <vector>
#include <stdbool.h>

using namespace std;

int N;
vector<int> W(1000);

vector<bool> memo(10000, false);

int sum = 0;

int main()
{
	cin >> N;
	for( int i = 0; i < N; i++ ) {
		cin >> W[i];
		sum += W[i];	
	}
	if( sum%2 == 1 ) {
		cout << "impossible" << endl;
		return 0;
	}

	sum = sum/2;

	for( int i = 0; i < N; i++ ) {
		vector<bool> newmemo(10000,false);

		newmemo[W[i]] = true;
		for( int j = 0; j < sum; j++ ) {
			if( memo[j] == true ) {
				newmemo[j+W[i]] = true;
			}
		}	
		for( int j = 0; j <= sum; j++ ) {
			// cout << j << " " << memo[j] << " " << newmemo[j] << endl;
			memo[j] = memo[j]  | newmemo[j];
		}
	}
	if( memo[sum] == true ) {
		cout << "possible" << endl;
		return 0;
	}
	else {
		cout << "impossible" << endl;
	}

	return 0;
}