//
//  main.cpp
//  Q19
//
//  Created by AkihiroKOBAYASHI on 7/6/15.
//  Copyright (c) 2015 Akhr5884. All rights reserved.
//

#include <iostream>

int *w;
int sum;
int n;
int check;

void judge(int nowWeight, int nowNumber) {
    if(check != 1 && nowNumber < n) {
        if(nowWeight == sum-nowWeight) {
            check = 1;
            return;
        }
        else if(nowWeight < sum-nowWeight){
            // add
            judge(nowWeight, nowNumber + 1);
            
            // not add
            judge(nowWeight + w[nowNumber], nowNumber + 1);
        }
    }
    return;
}

int main(int argc, const char * argv[]) {

    std::cin >> n;
    w = (int*)malloc(sizeof(w) * n);
    
    int count = 0;
    sum = 0;
    while (count < n) {
        int wi;
        std::cin >> wi;
        w[count] = wi;
        sum += wi;
        count++;
    }
    
    check = 0;
    if(sum%2 == 0) {
        judge(0, 0);
    }
    
    if(check == 1) {
        std::cout << "possible" << "\n";
    }
    else {
        std::cout << "impossible" << "\n";
    }

    return 0;
}