#include "bits/stdc++.h"

using namespace std;

#define FOR(i, j, k) for(int i = j; i < k; ++i)
#define rep(i, j) FOR(i, 0, j)
#define FORr(i, j, k) for(int i = j; i >= k; --i)
#define repr(i, j) FOR(i, j, 0)
#define INF (1 << 30)

typedef long long ll;
typedef unsigned long long ull;
typedef pair<int, int> P;
typedef pair<P, int> Pi;

const int MOD = 1e9 + 7;
const int dy[] = { 0, 0, 1, -1 };
const int dx[] = { 1, -1, 0, 0 };

template <class T> void chmin(T& a, const T& b) { a = min(a, b); }
template <class T> void chmax(T& a, const T& b) { a = max(a, b); }

bool dp[101][10001];

int main() {
	int N, W[100];
	int sum = 0;
	scanf("%d", &N);
	memset(dp, false, sizeof(dp));
	rep(i, N) {
		scanf("%d", &W[i]);
		sum += W[i];
	}
	dp[0][0] = true;
	rep(i, N) {
		rep(j, 10001) {
			if (dp[i][j]) {
				dp[i + 1][j + W[i]] = true;
				dp[i + 1][j] = true;
			}
		}
	}
	(dp[N][sum / 2]) ? printf("possible\n") : printf("impossible\n");
	return 0;
}