#include <iostream>
#include <sstream>
#include <string>
#include <vector>
#include <list>
#include <stack>
#include <queue>
#include <deque>
#include <set>
#include <map>
#include <algorithm>
#include <functional>
#include <limits>
#include <cstdio>
#include <cstdlib>
#include <cmath>
#include <climits>
#include <complex>

using namespace std;

#define INF (INT_MAX/3)
#define PI (2*acos(0.0))
#define EPS (1e-8)

typedef long long ll;
typedef unsigned long long ull;

int memo[101][10001], W[100], N;

void init(){
    for(int i = 0; i <= 100; i++){
        for(int j = 0; j <= 10000; j++){
            memo[i][j] = -1;
        }
    }
}

bool judge(int i, int left, int right){
    if(memo[i][left] >= 0) return (bool)memo[i][left];
    if(i == N) return left == right;
    
    return memo[i][left] = judge(i + 1, left + W[i], right) || judge(i + 1, left, right + W[i]);
}

int main(){
    ios_base::sync_with_stdio(0);
    init();
    cin >> N;
    for(int i = 0; i < N; i++) cin >> W[i];
    if(judge(0, 0, 0)) cout << "possible" << endl;
    else cout << "impossible" << endl;
    return 0;
}