#include <bits/stdc++.h>
using namespace std;
typedef long long ll;

bool dp[110][10010];
int main() {
    ios::sync_with_stdio(false);
    int n; cin >> n;
    int a[n];
    ll sum = 0;
    for (int i = 0; i < n; i++) {
        cin >> a[i];
        sum += a[i];
    }
    sort(a, a+n);

    if (sum & 1) {
        cout << "impossible\n";
        return 0;
    }
    ll half = sum / 2;
    ll w = a[0];
    dp[0][w] = true;

    for (int i = 1; i < n; i++) {
        for (int w = 0; w < 10010; w++)
            dp[i][w] = dp[i-1][w];

        ll t = a[i];
        dp[i][t] = true;
        for (int w = 0; w < 10010; w++) {
            if (dp[i-1][w])
                dp[i][w+t] = true;
        }
    }
    if (dp[n-1][half])
        cout << "possible\n";
    else
        cout << "impossible\n";



    return 0;
}