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

int N;
vector<int> W(101, 0);
bool dp[10001] = {0};

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