#include <iostream>
//#include<atcoder/all>
#include <numeric>
#include <cmath>
#include <limits>
#include <stdio.h>
#include <iomanip>
#include <string> 
#include <vector>
#include <algorithm>
#include <utility> 
#include <tuple> 
#include <cstdint> 
#include <cstdio> 
#include <map> 
#include <queue>
#include <set> 
#include <stack> 
#include <deque> 
#include <unordered_map> 
#include <unordered_set>
#include <bitset> 
#include <cctype>
//using namespace atcoder;
using namespace std;
using ll = long long;
#define all(A) A.begin(),A.end()
using vll = vector<ll>;
#define rep(i, n) for (long long i = 0; i < (long long)(n); i++)
using Graph = vector<vector<pair<ll, ll>>>;
vector<bool> seen;
bool C = true;
vector<ll> dist;
ll mod =1e9+7;
int op(int a, int b) {
	return min(a, b);
}
int e() {
	return int(1e9);
}

int main() {
	ll N;
	cin >> N;
	vll W(N);
	ll S = 0;
	rep(i, N) {
		cin >> W[i];
		S += W[i];
	}
	if (S % 2 != 0) {
		cout << "impossible" << endl; return 0
			;
	}


	vector<vector<bool>> DP(N+1, vector<bool>(10001, false));
	DP[0][0] = true;
	rep(i, N) {
		rep(w, 10001) {
			if (DP[i][w]) {
				DP[i + 1][w] = true;
				DP[i + 1][w + W[i]] = true;
			}
		}
	}
	if (DP[N][S / 2]) {
		cout << "possible" << endl;
	}
	else {
		cout << "impossible" << endl;
	}
}