//#include <bits/stdc++.h>

#include <iostream>
#include <algorithm>
#include <vector>
#include <string>
#include <cstring>
#include <complex>
#include <stack>
#include <queue>
#include <unordered_map>
#include <map>
 
#define INF 10e9
#define rep(i, a) for (int i = 0; i < (a); i++)
using namespace std;
 
int main() {
    int n;
    cin >> n;

    vector<int> w(n);
    int i, j;
    int A = 0;
    for(i = 0; i < n; i++){
        cin >> w[i];
        A += w[i];
    }

    bool dp[110][10010];

    if(A%2 != 0){
        cout << "impossible" << endl;
        return 0;
    }

    dp[0][0] = true;
    A /= 2;
    for(j = 1; j <= A; j++){
        dp[0][j] = false;
    }

    for(i = 0; i < n; i++){
        for(j = 0; j <= A; j++){
            if(j >= w[i]){
                dp[i+1][j] = (dp[i][j] || dp[i][j-w[i]]);
            }else{
                dp[i+1][j] = dp[i][j];
            }
        }
    }

    if(dp[n][A]){
        cout << "possible" << endl;
    }else{
        cout << "impossible" << endl;
    }
}