#include <iostream>
#define REP(i,a,b) for(i=a;i<b;i++)
#define rep(i,n) REP(i,0,n)
using namespace std;
int main() {
  int i,j,k;
  int N;
  int dp[11000] = {1};
  int sum = 0;
  cin >> N;
  rep(i,N) {
    int w;
    cin >> w;
    for(j=sum;j>-1;j--) {
      if(dp[j]) dp[j+w] = 1;
    }
    sum += w;
  }
  if(sum % 2 == 0 && dp[sum/2]) {
    puts("possible");
  }
  else puts("impossible");
}