#include <iostream>
#include <string>
#include <algorithm>
#include <iomanip>
#include <vector>
#include <map>
#include <cmath>
#include <queue>
#include <utility>
#include <functional>
#include <deque>
#include <cctype>
#include <stack>
#include <bitset>
#include <set>

using ll = long long;
using namespace std;
typedef unsigned long long ull;
typedef pair<ll, ll> P;

const ll MOD = 1000000007;
const ll INF = 1 << 30;
const ll INF2 = 9000000000000000000LL;
const double INF3 = 900000000000000;
const int dx[4] = { 1,0,-1,0 }, dy[4] = { 0,1,0,-1 };
const int tx[8] = { -1,0,1,-1,1,-1,0,1 }, ty[8] = { -1,-1,-1,0,0,1,1,1 };
#define ALL(x) (x).begin(),(x).end()



int main() {
	int n, w[110], sum = 0;
	bool dp[110][10010] = { 0 };
	cin >> n;
	for (int i = 0;i < n;i++) {
		cin >> w[i];
		sum += w[i];
	}
	if (sum % 2 == 1) {
		cout << "impossible" << endl;
		exit(0);
	}
	dp[0][0] = true;
	for (int i = 0;i < n;i++) {
		for (int j = 0;j <= 10000;j++) {
			if (dp[i][j]) {
				dp[i + 1][j] = true;
				dp[i + 1][j + w[i]] = true;
			}
		}
	}
	if (dp[n][sum / 2])cout << "possible" << endl;
	else cout << "impossible" << endl;
}