#include <iostream>
#include <string>
#include <algorithm>
#include <vector>
#include <iomanip>
#include <cmath>
#include <stdio.h>
#include <queue>
#include <deque>
#include <cstdio>
#include <set>
#include <map>
#include <bitset>
#include <stack>
#include <cctype>
using namespace std;
bool dp[110][10100] = { false };
int main() {	
	int n;
	cin >> n;
	int w[110];
	int sum = 0;
	for (int i = 0; i < n; i++) {
		cin >> w[i];
		sum += w[i];
	}
	if (sum % 2 == 1) {
		cout << "impossible" << endl;
		return 0;
	}
	else {
		dp[0][0] = true;
		sum /= 2;
		for (int i = 0; i < n; i++) {
			for (int j = 0; j <= sum; j++) {
				if (dp[i][j]) {
					dp[i + 1][j] = true;
					dp[i + 1][j + w[i]] = true;
				}
			}
		}
	}
	if (dp[n][sum]) {
		cout << "possible" << endl;
	}
	else {
		cout << "impossible" << endl;
	}
	return 0;
}