#include <vector>
#include <list>
#include <map>
#include <set>
#include <deque>
#include <stack>
#include <bitset>
#include <algorithm>
#include <functional>
#include <numeric>
#include <utility>
#include <sstream>
#include <iostream>
#include <iomanip>
#include <cstdio>
#include <cmath>
#include <cstdlib>
#include <cctype>
#include <string>
#include <cstring>
#include <ctime>

using namespace std;

#define INF 1000000000
#define EPS 1e-9
#define PI acos(-1)

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

#define MAX_N 100

int N;
int W[MAX_N];

int dp[MAX_N+1][MAX_N * MAX_N + 1];

int main(){
  
  cin >> N;
  int sum = 0;
  for(int i = 0; i < N; i++){
    cin >> W[i];
    sum += W[i];
  }

  dp[0][0] = 1;

  for(int i = 0; i < N; i++){
    for(int j = 0; j <= MAX_N * MAX_N; j++){
      dp[i+1][j] |= dp[i][j];
      if(j - W[i] >= 0)
	dp[i+1][j] |= dp[i][j-W[i]];
    }
  }

  if(sum%2 == 0 && dp[N][sum/2] == 1)
    cout << "possible" << endl;
  else
    cout << "impossible" << endl;
  
  return 0;

}