#include <bits/stdc++.h>
using namespace std;
int N, S;
vector<int> W;

int dp[101][10001];

void recursive(int pos, int weight) {
	if(pos > N || dp[pos][weight]) return;
	dp[pos][weight] = 1;
	recursive(pos + 1, weight);
	recursive(pos + 1, weight + W[pos]);
}

int main() {
	cin >> N;
	W = vector<int>(N + 1);
	S = 0;
	for(int i = 0; i < N; i++) {
		cin >> W[i];
		S += W[i];
	}
	W[N] = 0;
	for(int i = 0; i < 101; i++) {
		for(int j = 0; j < 10001; j++) {
			dp[i][j] = 0;
		}
	}
	if(S % 2 == 1) {
		cout << "impossible" << endl;
		return 0;
	}
	recursive(0, 0);
	if(dp[N][S / 2]) {
		cout << "possible" << endl;
	} else {
		cout << "impossible" << endl;
	}
	return 0;
}