#include <bits/stdc++.h>

int main() {
	
	int N;
	std::cin >> N;
	std::vector<int> W(N);
	for(auto&v:W)std::cin >> v;
	int sum = std::accumulate(begin(W),end(W),0);
	std::vector<std::vector<bool>> dp(N+1,std::vector<bool>(sum/2+1,0));
	dp[0][0]=true;
	for(int i=0;i<N;++i){
		for(int j=0;j<=sum/2;++j){
			if(W[i]<=j)
				dp[i+1][j] = dp[i][j-W[i]] || dp[i][j];
			else
				dp[i+1][j] = dp[i][j];
		}
	}
	bool ans = dp[N][sum/2] && !(sum&1);
	std::cout << (ans?"possible":"impossible") << std::endl;
}