#include <iostream>
#include <vector>

auto main() -> int {
	int n;
	std::cin >> n;

	int sum = 0;
	int dp[100*100+1];
	dp[0] = 1;
	for (int i = 0; i < n; i++) {
		int w;
		std::cin >> w;

		sum += w;
		for (int i = 100*99; i >= 0; i--) {
			dp[i+w] += dp[i];
		}
	}

	if ((sum%2 == 0) && (dp[sum/2] != 0)) {
		std::cout << "possible" << std::endl;
	} else {
		std::cout << "impossible" << std::endl;
	}
}