#include <bits/stdc++.h>

#define all(x) begin(x), end(x)
#define times(x) for (int _ = 0 ; _ < (int)(x) ; _++)

using i32 = int;
using i64 = long long;
using ld = long double;
using usize = std::size_t;

template <class T1, class T2>
inline bool chmax(T1 &a, const T2 &b) { return a < b and (a = b, true); }
template <class T1, class T2>
inline bool chmin(T1 &a, const T2 &b) { return a > b and (a = b, true); }

constexpr i64 supl = (std::numeric_limits<i64>::max() >> 1) - 100;
constexpr i32 supi = (std::numeric_limits<i32>::max() >> 1) - 100;



namespace zawa::input {

template <typename T> 
void in(T& res) { std::cin >> res; }

template <typename Head, typename... Tail>
void in(Head& head, Tail&... tail) { in(head); in(tail...); }

template <typename T, typename U>
void in(std::pair<T, U>& res) { in(res.first); in(res.second); }

template <typename T>
void in(std::vector<T>& res) { for (auto& r : res) { in(r); } }

} // namespace zawa::input
using zawa::input::in;



namespace zawa::output {

void out() { 
    std::cout << std::endl; 
}

template <class T>
void out(const T& a) { 
    std::cout << a << std::endl; 
}

template <class T>
void out(const std::vector<T>& as) { 
    for (std::size_t i = 0 ; i < as.size() ; i++) { 
        std::cout << as[i] << (i + 1 == as.size() ? '\n' : ' '); 
    } 
}

template <class Head, class... Tail>
void out(const Head& head, const Tail&... tail) { 
    std::cout << head; 
    if (sizeof...(tail)) { 
        std::cout << ' '; 
    } 
    out(tail...);
}

void yesno(bool flag, std::string yes = "Yes", std::string no = "No") {
    std::cout << (flag ? yes : no) << std::endl;
}

} // namespace zawa::output
using zawa::output::out;
using zawa::output::yesno;



namespace zawa::util {

template <class T>
std::vector<T> sorted(std::vector<T> A) {
	std::sort(A.begin(), A.end());
	return A;
}

std::string sorted(std::string s) {
	std::sort(s.begin(), s.end());
	return s;
}

} // namespace zawa::util


namespace zawa::util {

template <class T>
std::vector<T> reversed(std::vector<T> A) {
	std::reverse(A.begin(), A.end());
	return A;
}

std::string reversed(std::string s) {
	std::reverse(s.begin(), s.end());
	return s;
}

} // namespace zawa::util
using namespace zawa::util;

// #include "atcoder/modint"
// using mint = atcoder::modint998244353;
// using mint = atcoder::modint1000000007;

// #include "src/template/accum1d.hpp"
// #include "src/template/binary-search.hpp"
// #include "src/template/binary-search-ld.hpp"
// #include "src/algorithm/compression.hpp"
// #include "src/algorithm/RLE.hpp"

// #include "src/graph/Read-Graph.hpp"
// #include "src/graph/Read-Weighted-Graph.hpp"

using namespace std;

void main_() {
	i32 n; in(n);
	bitset<10100> dp(1);
	i32 s = 0;
	times(n) {
		i32 w; in(w);
		s += w;
		dp = dp | (dp << w);
	}
	if (s % 2 == 0 and dp[s / 2]) out("possible");
	else out("impossible");
}

i32 main() {
	ios::sync_with_stdio(false);
	cin.tie(nullptr);
	cout << fixed << setprecision(15);

	main_();

	return 0;
}