#include <algorithm>
#include <cmath>
#include <cstring>
#include <iostream>
#include <map>
#include <numeric>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <vector>
#include <iterator>

#define pb push_back
#define puts(x) cout << #x << " : " << x << endl;
#pragma GCC diagnostic ignored "-Wconversion"

#define REP(i,n) for (int i=0;i<(n);i++)
#define REPE(i,n) for (int i=0;i<=(n);i++)

#define init(a,b) memset((a), (b), (sizeof(a)));

#define PI 3.14159265
#define EPS (1e-10)
#define EQ(a,b) (abs((a)-(b)) < EPS)

using namespace std;

typedef long long ll;
typedef pair<int, int> P;

bool dp[105][5005];
int W[200];
int total_weight = 0;
int half_weight = 0;

int main() {
    int N;cin>>N;
    for(int i=0;i<N;i++){
        cin>>W[i];
        total_weight += W[i];
    }
    if(total_weight % 2){
        cout<<"impossible"<<endl;
        return 0;
    }

    half_weight = total_weight / 2;

    for(int i=0;i<N;i++){
        dp[i][0] = 1;
        for(int j=0; j <= half_weight;j++){
            if(j-W[i]>=0){
                // use
                dp[i + 1][j] |= dp[i][j - W[i]];
            }
            // no use
            dp[i + 1][j] |= dp[i][j];
        }
    }

//    for(int i=0;i<N;i++){
//        for(int j=0;j<=half_weight;j++){
//            cout<<dp[i][j]<<':';
//        }
//        cout<<endl;
//    }

    if(dp[N][half_weight]){
        cout<<"possible"<<endl;
    }else{
        cout<<"impossible"<<endl;
    }

    return 0;
}