#include <iostream>
#include <vector>
#include <cstring>
using namespace std;

const int kMAX_N = 110;
const int kMAX_W = 110;

bool can_adjust[2][kMAX_W * kMAX_N];
int N;
vector<int> W;

void Solve() {
    memset(can_adjust, false, sizeof(can_adjust));

    int sum = 0;
    for (int i = 0; i < N; i++) {
        sum += W[i];
    }

    if (sum % 2 == 1) {
        cout << "impossible" << endl;
        return;
    }

    bool* cur = can_adjust[0], * next = can_adjust[1];
    cur[0] = true;
    for (int i = 0; i < N; i++) {
        for (int j = 0; j <= sum; j++) {
            next[j] |= cur[j];
            if (j - W[i] >= 0) {
                next[j] |= cur[j - W[i]];
            }
        }
        swap(cur, next);
    }

    if (next[sum / 2]) cout << "possible" << endl;
    else cout << "impossible" << endl;
}

int main() {
    cin >> N;

    W = vector<int>(N);

    for (int i = 0; i < N; i++) {
        cin >> W[i];
    }

    Solve();

    return 0;
}