#include <bits/stdc++.h> 

using i64 = long long; 
using u64 = unsigned long long; 
using u32 = unsigned; 

using u128 = unsigned __int128; 
using i128 = __int128; 

void solve() {
	int N;
	std::cin >> N;

	int sum = 0;

	std::vector<int> W(N);
	for(int& x : W) {
		std::cin >> x;
		sum += x;
	}	

	if(sum % 2) {
		std::cout << "impossible";
		return;
	}

	int x = sum / 2;

	std::vector<bool> dp(x + 1);

	dp[0] = true;

	for(int i = 0; i < N; i ++) {
		for(int j = x; j >= W[i]; j --) {
			dp[j] = dp[j] | dp[j - W[i]];
		}
	}

	if(dp[x]) std::cout << "possible";
	else std::cout << "impossible";
} 	

int main() { 
	std::ios::sync_with_stdio(false); 
	std::cin.tie(nullptr); 

	int T = 1; 
	//std::cin >> T; 

	while (T--) { 
		solve(); 
	} 
	return 0; 
}