#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
const int MOD = 1000000007;
const int MAX_N = 110;

#define REP(i,n) for((i)=0;(i)<(int)(n);(i)++)

int w[MAX_N];
bool dp[MAX_N][10010];

int main(){
    int Sum = 0;
    int n;
    cin >> n;
    for (int i = 0; i < n; i++){
        cin >> w[i];
        Sum += w[i];
    }

    if (Sum % 2 == 1) cout << "impossible" << endl;
    else{
        Sum /= 2;

        dp[0][0] = true;

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

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

    return 0;
}