#include <iostream>
#include <vector>
#include <algorithm>
#include <map>
#include <string>
#include <queue>
#include <stack>
#include <math.h>
#include <set>
#define ALL(obj) (obj).begin(),(obj).end()
#define RALL(obj) (obj).rbegin(),(obj).rend()
#define P pair<int, int>

#define MOD 1000000007
#define INF 2147483647
#define NINF (-2147483647-1)
#define LLINF 9223372036854775807
using ll = long long;
using namespace std;

int main() {
    int N, sum = 0;
    cin >> N;
    vector<int> W(N);
    for (int i = 0; i < N; i++)
    {
        cin >> W[i];
        sum += W[i];
    }
    if (sum % 2 == 0) {
        sum /= 2;
        // dp[i][j] := i番目までの数字を使ってjが作れるか
        vector<vector<bool>> dp(N+1, vector<bool>(sum + 1, false));
        dp[0][0] = true;
        for (int i = 0; i < N; i++)
        {
            for (int j = 0; j <= sum; j++)
            {
                if (dp[i][j]) {
                    dp[i + 1][j] = true;
                }
                if (j + W[i] <= sum && dp[i][j]) {
                    dp[i + 1][j + W[i]] = true;
                }
            }
        }
        if (dp[N][sum]) {
            cout << "possible" << endl;
        }
        else {
            cout << "impossible" << endl;
        }
    }
    else {
        cout << "impossible" << endl;
    }
    getchar(); getchar();
    return 0;
}