#include <iostream>

using namespace std;
using LL = long long;

bool dp[101][10001];

int main() {
    int N;
    cin >> N;

    dp[0][0] = true;
    int W, sum = 0;
    for (int i = 1; i <= N; i++) {
        cin >> W;
        for (int j = 0; j <= sum; j++) {
            if (dp[i - 1][j]) {
                dp[i][j] = true;
                dp[i][j + W] = true;
            }
        }
        sum += W;
    }

    bool ans = false;
    if (sum % 2 == 0) {
        for (int i = 1; i <= N; i++) {
            if (dp[i][sum / 2]) {
                ans = true;
                break;
            }
        }
    }

    cout << (ans ? "possible" : "impossible") << endl;
}