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

int N;
vector<int> W(100, 0);
int dp[101] = {0};

int main(void){
    
    cin >> N;
    int sum = 0;
    for(int i = 0; i < N; ++i){
        cin >> W[i];
        dp[i] = W[i];
        sum += W[i];
    }
    
    if(sum % 2 == 0){
        for(int i = 0; i < N; ++i){
            for(int j = i + 1; j < N; ++j){
                dp[j] = W[i] + dp[j];
                if(dp[j] == sum / 2){
                    cout << "possible" << endl;
                    return 0;
                }
            }
        }
    }
    cout << "impossible" << endl;
    
    return 0;
}