#define _CRT_SECURE_NO_WARNINGS
#include <iostream>
#include <iomanip>
#include <stdio.h>
#include <numeric>
#include <math.h>
#include <algorithm>
#include <functional>
#include <cstring>
#include <array>
#include <vector>
#include <list>
#include <stack>
#include <set>
#include <map>
#include <unordered_set>
#include <unordered_map>
#include <deque>
#include <queue>
#include <complex>
#include <bitset>
#define full(c) c.begin(), c.end()
#define vector2d(name,type,h,w,init) vector<vector<type>> name(h,vector<type>(w,init)) 
const int PRIME = 1000000007;
const int INT_INF = 2147483647;
const long long int LL_INF = 9223372036854775807;
const double PI = acos(-1);
const double EPS = 0.0001;
typedef unsigned long long int ull;
typedef long long int ll;
using namespace std;

int main() {
	//cin.tie(0);
	//ios::sync_with_stdio(false);
	const int INF = 2e9;
	const int TOP = 10090;
	int n, sum;
	cin >> n;
	vector<bool> can(TOP, false);
	can[0] = true;
	sum = 0;
	for (int k = 0; k < n; k++) {
		int a;
		cin >> a;
		for (int i = TOP; i >= a; i--) {
			if (can[i - a]) can[i] = true;
		}
		sum += a;
	}
	if (sum % 2 == 0 && can[sum / 2]) cout << "possible" << endl;
	else cout << "impossible" << endl;
	return 0;
}