#include <iostream>
#include <cstdio>
#include <cmath>
#include <vector>
#include <deque>
#include <list>
#include <string>
#include <stack>
#include <queue>
#include <set>
#include <map>
#include <algorithm>

using namespace std;

bool dp[101][5010];

int N;
int W[101];
int sum;

int main() {
	int i, j;
	bool flag = false;

	cin >> N;

	sum = 0;
	for (i = 0; i < N; i++) {
		cin >> W[i];
		sum += W[i];
	}
	
	if (sum % 2) {
		cout << "impossible" << endl;
		return 0;
	}
	sum /= 2;

	dp[0][0] = true;
	for (i = 0; i < N && !flag; i++) {
		for (j = 0; j < sum; j++) {
			if (dp[i][j]) {
				if (j + W[i] == sum) {
					flag = true;
					break;
				}
				dp[i+1][j] = true;
				dp[i+1][j+W[i]] = true;
			}
		}
	}

	if (flag) cout << "possible" << endl;
	else cout << "impossible" << endl;

	return 0;
}