#include<iostream>
#include<cstdio>
#include<cstring>
#include <cstdlib>  
#include <cmath>   
#include<cctype>
#include<string>
#include<set>
#include<iomanip>
#include <map>
#include<algorithm>
#include <functional>
#include<vector>
#include<climits>
#include<stack>
#include<queue>
#include <deque>
#include <climits>
#include <typeinfo>
#include <utility> 
#define all(x) (x).begin(),(x).end()
#define rep(i,m,n) for(int i = m;i < n;++i)
#define pb push_back
#define fore(i,a) for(auto &i:a)
#define rrep(i,m,n) for(int i = m;i >= n;--i)
#define INF INT_MAX/2
using namespace std;
using ll = long long;
using R = double;
using Data = pair<ll, vector<int>>;
const ll MOD = 1e9 + 7;
const ll inf = 1LL << 50;
struct edge { ll from; ll to; ll cost; };

vector<int>w(110);
int dp[110][10010];
int n,sum;

string solve() {
	dp[0][0] = 1;
	rep(i,0,n)rep(j,0,sum+1){
		dp[i+1][j+w[i]] += dp[i][j];
		dp[i + 1][j] += dp[i][j];
	}
	if (dp[n][sum / 2] > 0)return "possible";
	else return "impossible";
}


int main() {
	cin >> n;
	sum = 0;
	rep(i, 0, n) {
		cin >> w[i];
		sum += w[i];
	}

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

	return 0;
}