#include <algorithm>
#include <cstdio>
#include <iostream>
#include <map>
#include <math.h>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <vector>
using namespace std;

#define ll long long
#define INF (1 << 30)
#define INFLL (1LL << 60)

int n,w[101],sum = 0;
bool can[5010] = {};

bool bfs(int now,int num){
	bool ans = 0,ans2 = 0;
	if(num == sum / 2) return true;
	if(now == n) return false;
	if(num > sum / 2) return false;
	ans = bfs(now + 1,num + w[now]);
	ans2 = bfs(now + 1,num);
	return ans || ans2;
	return ans;
}

int main() {
	cin >> n;
	for(int i = 0;i < n;i++){
		cin >> w[i];
		sum += w[i];
	}
	if(sum % 2 == true)cout << "impossible" << endl;
	else if(bfs(0,0))cout << "possible" << endl;
	else cout << "impossible" << endl;
	return 0;
}