#define  _CRT_SECURE_NO_WARNINGS
#include <stdio.h>
#include <algorithm>
#include <utility>
#include <functional>
#include <cstring>
#include <queue>
#include <stack>
#include <math.h>
#include <iterator>
#include <vector>
#include <string>
#include <set>
#include <math.h>
#include <iostream> 
#include<map>
#include <iomanip>
#include <stdlib.h>
#include <list>
#include <typeinfo>
#include <list>
#include <set>
using namespace std;
#define MAX_MOD 1000000007
#define REP(i,n) for(long long i = 0;i < n;++i)
#define LONG_INF 100000000000000
int possible[200][20000] = {};
int main() {
	int n;
	cin >> n;
	int ans = 0;
	vector<int> d;
	for (int i = 0;i < n;++i) {
		int cm;
		cin >> cm;
		ans += cm;
		d.push_back(cm);
	}
	if (ans % 2 == 1) {
		cout << "impossible" << endl;
		return 0;
	}
	ans /= 2;
	possible[0][0] = 1;
	for (int i = 1;i <= n;++i) {
		for (int q = 0;q <= ans;++q) {
			possible[i][q] = max(possible[i][q], possible[i - 1][q]);
			if (d[i - 1] + q <= ans) {
				possible[i][q + d[i - 1]] = max(possible[i][q + d[i - 1]], possible[i - 1][q]);
			}
		}
	}
	if (possible[n][ans] == true) {
		cout << "possible" << endl;
		return 0;
	}
	else {
		cout << "impossible" << endl;
		return 0;
	}
}