//yukicoder 4
#include <bits/stdc++.h>
using namespace std;

int n, weight;
int w[100];
int dp[101][10001];

int dfs(int i, int sum) {
	if(dp[i][sum] >= 0) return dp[i][sum];
	if(i == n) return (double)sum == ((double)weight / 2);
	if(dfs(i + 1, sum)) return 1;
	if(dfs(i + 1, sum + w[i])) return 1;
	return 0;
}

int main() {
	cin >> n;
	for(int i = 0; i < n; i++) {
		cin >> w[i];
		weight += w[i];
	}
	for(int i = 0; i < 101; i++) {
		for(int j = 0; j < 10001; j++) dp[i][j] = -1;
	}
	if(dfs(0, 0)) cout << "possible";
	else cout << "impossible";
	cout << endl;
	return 0;
}