#include<cstdio>
#include<iostream>
#include<algorithm>
#include<string>
#include<cstring>
#include<queue>
#include<vector>
#include<functional>
#include<cmath>
#include<map>
#include<stack>
#include<set>
#include<numeric>
#include<limits>
#include<iterator>

#define all(x) (x).begin(),(x).end()
#define rall(x) (x).rbegin(),(x).rend()
#define rep(i,n) for(int i=0; i<n; i++)
#define FOR(i,a,n) for(int i=a; i<n; i++)

using namespace std;
typedef long long ll;
typedef pair<int, int> pi;
typedef pair<ll, ll> pl;
typedef pair<ll, char> plc;
typedef pair<string, string> pss;

int n,sum;
int w[110];
int dp[110][110];

int main()
{
	cin >> n;

	rep(i, n) {
		cin >> w[i+1];
		sum += w[i+1];
	}

	if (sum % 2 != 0) {
		cout << "impossible" << endl;
		return 0;
	}

	dp[0][0] = 0;

	for (int i = 1; i <= n; i++) {
		for (int j = 0; j <= sum/2; j++) {
			if (j < w[i]) {
				dp[i][j] = dp[i - 1][j];
			}else{
				dp[i][j] = max(dp[i - 1][j-w[i-1]]+w[i],
					dp[i-1][j]);
			}
		}
	}

	for (int i = 1; i <= n; i++) {
		for (int j = 0; j <= sum/2; j++) {
			if (dp[i][j] == sum / 2) {
				cout << "possible" << endl;
				return 0;
			}
		}
	}
	cout << "impossible" << endl;
	return 0;
}