#include <iostream>
#include <algorithm>
#include <vector>
#include <cstdio>
using namespace std;
#define rep(i,n) for(int i=0;i<(n);i++)

bool dp[101][10001];
int main(void){
    rep(i, 101)rep(j, 10001) dp[i][j] = false;
    int n; cin >> n;
    vector<int> w(n);
    rep(i, n)cin >> w[i];

    int sum = 0;
    rep(i, n) sum += w[i];
    if(sum % 2 == 1){
        printf("impossible\n");
        return 0;
    }

    dp[0][0] = true;
    for (int i = 0; i < n ; ++i){
        for (int j = 0; j <= 10000; ++j){
            if(dp[i][j] == true){
                dp[i + 1][j + w[i]] = true;
                dp[i + 1][j] = true;
            }
        }
    }

    if(dp[n][sum / 2] == true) printf("possible\n");
    else printf("impossible\n");
    return 0;
}