#include<cstdio>
#include <iostream>
#include<algorithm>
#include<string>
#include<queue>
#include<vector>
#include<functional>
#include<cmath>
#include<map>
#include<stack>
#include<set>
using namespace std;
typedef long long ll;
//typedef pair<int, int> P;

int w[101],P[101];
int N,sum,res1,res2,flag=0;

void solve() {
	for (int i = 0; i < N; i++) {
		if (P[i]) {
			res1 += w[i];
		}
		else {
			res2 += w[i];
		}
	}

	if (res1 == res2) {
		flag = 1;
	}
}

 void Set(int x) {
	if (x >= N) {
		res1 = res2 = 0;
		solve();
		return;
	}
	for (int i = 0; i < 2; i++) {
		P[x] = i;
		Set(x + 1);
	}
}

int main()
{
    cin >> N;
	
	for (int i = 0; i < N; i++) {
		cin >> w[i];
		sum += w[i];
	}

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