#define _USE_MATH_DEFINES
#define _CRT_SECURE_NO_WARNINGS
#include<stdio.h>
#include<string>
#include<iostream>
#include<cctype>
#include<cstdio>
#include<vector>
#include<stack>
#include<queue>
#include <algorithm>
#include<math.h>
#include<set>
#include<map>
#include <sstream>
#include<iomanip>

//#include<bits/stdc++.h>


using namespace std;
bool f[10105];
int main() {
	int n;
	cin >> n;
	int s =0 ;
	f[0] = 1;
	for (int i = 0; i < n; i++) {
		int x;
		cin >> x;
		s += x;
		for (int j = 10000; j >= 0; j--)
			if(f[j])f[j + x] =1;

	}
	//cout << s;
	//cout << f[s / 2];
	if (s % 2||!f[s/2])cout << "impossible" << endl;
	else cout << "possible" << endl;
	return 0;
}