#include <iostream>
#include <algorithm>
#include <string>
#include <cstring>
using namespace std;

#define REP(i,a,b) for(i=a;i<b;i++)
#define rep(i,n) REP(i,0,n)
#define SQR(X) ((X)*(X))

typedef long long ll;
typedef unsigned long long ull;
typedef long double lb;
/* ここからが本編 */
static int dp[10010] = {1};
int main(void)
{
  int i,j,k,l;
  int n;
  int w;
  int sum = 0;
  /* 入力開始！ */
  cin >> n;
  for(i=0;i<n;i++) {
    cin >> w;
    for(j=sum;j>-1;j--) {
      if(dp[j]) dp[j+w] = 1;
    }
    sum += w;
  }
  /* 入力終了！ */
  if(sum%2 == 0 && dp[sum/2] == 1) cout << "possible" << endl;
  else cout << "impossible" << endl;
  return 0;
}