#include <sstream>
#include <string>
#include <vector>
#include <map>
#include <algorithm>
#include <iostream>
#include <utility>
#include <set>
#include <cctype>
#include <queue>
#include <stack>
#include <cstdio>
#include <cstdlib>
#include <cmath>

#define INF 1000000000

using namespace std;
typedef long long ll;

bool dp[110][10100];
int W[110];

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