#include <iostream>
#include <cstring>
using namespace std;

#define N 100
#define W 100

int n;
int w[N];
int wm[W*N+1];
int hw;

int dp()
{
	for ( int i = 0; i < n; i++ ) {
		if ( w[i] == hw ) {
			return 1;
		}
		for ( int j = hw - 1; j >= 1; j-- ) {
			if ( wm[j] == 1 ) {
				wm[j + w[i]] = 1;
			}
		}
		wm[w[i]] = 1;
		if ( wm[hw] == 1 ) {
			return 1;
		}
	}
	return 0;
}

int main()
{
	cin >> n;
	for ( int i = 0; i < n; i++ ) {
		cin >> w[i];
		hw += w[i];
	}
	if ( hw % 2 == 0 && (hw /= 2, dp() == 1) ) {
		cout << "possible" << endl;
	}
	else {
		cout << "impossible" << endl;
	}

	return 0;
}