#include <iostream>
#include <algorithm>
#include <vector>
#include <stdio.h>
#include <cmath>

using namespace std;
typedef uint uint32_t;

#define IM "impossible"
#define PO "possible"
int N;
// int W[100];
int sum = 0;
bool pos[100*101] = {0};


int main() {
    cin >> N;
    pos[0] = true;
    int W;
    for (int i = 0; i < N; i++) {
        cin >> W;
        sum += W;
        for (int j = 10000; j >= 0; j--) {
            if (pos[j]) pos[j+W] = true;
        }
    }
    if (sum % 2 ==0 && pos[sum/2]) cout << PO << endl;
    else cout << IM << endl;
    return 0;
}