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

bool dp[110][10011];
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];
    }
    if (sum & 1) {
        cout << "impossible\n";
        return 0;
    }
    dp[0][0] = true;
    
    for (int i = 0; i < n; i++) {
        for (int j = 0; j <= 10010; j++) {
            if (dp[i][j] == true) {
                dp[i+1][j + a[i]] = true;
                dp[i+1][j] = true;
            }
        }
    }
    if (dp[n][sum/2])
        cout << "possible\n";
    else
    {
        cout << "impossible\n";
    }
    
    

    return 0;
}