#include <iostream>

int n;
int w[101];
bool dp[101][10001];

int main(){
	std::cin >> n;
	for (int i = 0; i < n; i++)std::cin >> w[i];

	dp[0][0] = true;

	for (int i = 0; i < n; i++){
		for (int j = 0; j < 10001; j++){
			if (dp[i][j]){
				dp[i + 1][j] = true;
				dp[i + 1][j + w[i]] = true;
			}
		}
	}

	int sum = 0;
	for (int i = 0; i < n; i++)sum += w[i];

	if (sum & 1)std::cout << "impossible" << std::endl;
	else if (!dp[n][sum / 2])std::cout << "impossible" << std::endl;
	else std::cout << "possible" << std::endl;

	return 0;
}